Gem Listings Main Page
List of Gemstones By Name (A-Z)
Actinolite View Profile
Actinolite is a member of a series that contains varying amounts of iron and magnesium. Tremolite is the Mg end, and ferroactinolite the Fe end, with actinolite in the middle. Actinolites with more than 50% Fe are very rare. Catseye actinolite exists (S.G. 3.0, R.I. 1.63); when chatoyant material is cut, it exhibits a fine eye. Actinolite is easy to cleave and hard to cut and woul...
Adamite View Profile
Exceedingly rare as a cut gem, although the mineral occurs in many localities. Much too soft and fragile for jewelry; strictly a collector item.
Agate View Profile
Agate is a variety of chalcedony that exists in many colors and is often commercially dyed. Agate is distinguished by having multiple colors. While not usually as rich as our crystalline gems, the colors can be quite vivid. Agates are sometimes opaque, but they are frequently translucent, and occasionally completely transparent.
Albite View Profile
Albite, usually colorless but sometimes yellow, pink, gray or reddish. Translucent albite is sometime colored green by chrome jadeite. It is also a component of trachipe emeralds.
Alexandrite View Profile
Alexandrite is a remarkable gem. It is one of the finest color change stones in nature, resembling fine emerald or ruby, depending on the light source. It is so rare, that most people have never seen one. Yet, when the modern list of birthstones was assembled, it was listed as June's birthstone.
Algodonite View Profile
Cabochons of these arsenides are bright, silvery, and metallic and are both attractive and unusual. However, they tarnish rather quickly and the surfaces turn a drab brown and lose their luster. Cut stones are rarely seen even in collections, although they are strikingly beautiful when cut and polished to a high luster. They must be sprayed with lacquer to prevent tarnishing. Algodo...
Almandine View Profile
Almandine is perhaps the most common garnet. Gemstones always have some spessartine and pyrope components, and this creates a wide range of colors, including brown, red-brown, purplish red, wine red, purple, and deep red. Inclusions of asbestiform minerals (pyroxene or amphibole) create a chatoyancy that yields, in cabochons, a 4-rayed star.
Amber View Profile
Amber is classed in various types: sea amber (found in the sea), pit amber (dug up, especially from the Baltic area), clear, massive, fancy, cloudy, frothy, fatty, and bone amber.
Amblygonite View Profile
Amblygonite gems are usually pale straw yellow. Although they are too soft and cleavable to make good ring stones, collectors prize them if they show darker colors. Large faceted stones are extremely rare.
Amethyst View Profile
Crystalline quartz in colors ranging from pale lilac to deep reddish purple and ranging from transparent to translucent is known as amethyst. Siberian mines once produced the world's finest stones with particularly rich purple color that glowed with reddish and/or bluish highlights. Today the term Siberian no longer is a place designation as the mines are long since worked out, but ...
Ametrine View Profile
Quartz which occurs in bands of yellow and purple has been given the name of ametrine (amethyst + citrine). Originally discovered in Brazil, the world's current supply comes from one area in Bolivia. The crystals from this mine often exhibit an abrupt color transition, which probably reflects dramatic changes in temperature during their formation.
Ammolite View Profile
In 1981, ammolite became recognized by CIBJO, (the Colored Stones Commission.) It is the latest of only three new gemstones introduced in the last 50 years. It is also only one of three organic gemstones, (including amber & pearl.) It has been compared to opal and has a superficial similarity to the Austrian mineral lumachelle whose iridescence is also provided by the fossil amm...
Analcime View Profile
Large colorless crystals of Analcime are a great rarity although small transparent crystals are abundant. Faceted gems are extremely rare and seldom seen even in large collections. The hardness is marginal for wear, but the mineral has no cleavage and should present no difficulties in cutting.
Anatase View Profile
Anatase is usually found in very small crystals, seldom transparent, and even then very dark-colored. Gems have been cut as curiosities, but are almost never seen for sale on the market because of scarcity.
Andalusite View Profile
Andalusite is a slightly brittle material and care is required if it is set as a ringstone. The pleochroism of andalusite is distinctive and extremely attractive. Sometimes gems are cut to show the pink and almost colorless shades; others display green in the center with brown tips or various other combinations, depending on how the rough was oriented before cutting. Catseye andalus...
Andradite View Profile
Andradite is one of the rarest and most sought after garnets. There are no major sources of andradite and the supply is limited to small deposits.
Anglesite View Profile
Anglesite gems are colorless to pale brown and are available from only a few localities. The dispersion is equal to that of diamond, and property faceted gems are truly magnificent and bright. Low hardness and cleavage indicate great care is requires in cutting, and wear is not recommended. Cut anglesites are true rarities and seldom seen except in very complete collections.
Anhydrite View Profile
The blue or violet color disappears on heating and can be restored by gamma ray bombardment. The natural color may therefore be caused by natural radiation. Gemstones are very fragile due to excellent cleavages and must be cut and handled with great care.
Apatite View Profile
Fluorapatite is the commonest apatite variety. Apatite is abundant throughout the world, and is, in fact, the main constituent of bones and teeth. It is also the most abundant phosphorus-bearing mineral, especially cellophane, the massive type that makes up large beds in some localities. Apatite is brittle and heat sensitive, and must be cut and worn with care. Property cut stones...
Apophyllite View Profile
Although not suitable for jewelry, apophyllite is a popular collector's piece. Perhaps the whitest of all gems, cut, colorless specimens are so devoid of color they can appear almost silvery.
Aquamarine View Profile
Aquamarine is a member of the beryl family, as is emerald. Aqua is known for its blue or blue green coloring, which accounts for its name. The legends behind aquamarine all have to do with the sea and water.
Aragonite View Profile
Aragonite is more commonly found as a constituent of pearl and shell nacre than as a crystal suitable for gem cutting. Too soft for most jewelry use, a faceted aragonite would be a true collector's item.
Augelite View Profile
Augelite is soft and brittle, unsuited for wear. However, the gems cut from rare transparent crystals are true collector items and are seen only in very complete collections.
Axinite View Profile
Cut axinites are usually intensely trichroic, with the brown and purple colors dominating. The material is exquisite but is almost never completely free of flaws and feathers. Axinite is actually an extremely rare cut gem and could be on the most magnificent because of its rich colors and brilliance. Clean stones over 5 carats are difficult to find and worthy of museum display. Axin...
Azurite View Profile
Faceted azurite is a great rarity, but even small stones are extremely dark, virtually black. Azurmalachite is a mixture of azurite and another copper carbonate, malachite. Burnite is a mixture of azurite and cuprite (copper oxide). Azurite occurs in fine crystals in many localities, but in massive form is almost always mixed with malachite. In this form it is cut as very attrac...
Barite View Profile
Massive white barite looks like marble and could be used for decorative purposes. Faceted gems are hard to cut, and facet junctions tend to be rounded. The perfect cleavage makes wear very risky and the low hardness would also prevent use in jewelry. In spite of the abundance of good crystals, cut barites are not commonly seen, especially in rich colors. With very few exceptions, la...
Bayldonite View Profile
Bayldonite is a nondescript greenish material that has been cut into cabochons by enterprising collectors of the unusual. Cut bayldonites are a rarity, nonetheless, and are seldom seen in collections. The luster of cabochons is sometimes almost metallic and provides a curious appearance to the cut stones. Bayldonite provides a curious appearance to the cut stones. Bayldonite is comp...
Benitoite View Profile
With dispersion higher than diamond and sapphire blue body color, benitoite is one of the most attractive of all rare gems. Gem-quality crystals have been found only in San Benito County, California.
Beryl View Profile
The beryls are among the most popular, and also the most expensive, of all gems. A wide range of color is represented, from colorless to black. Beryls can be large and flawless, but these are best displayed in museums rather than worn. Emerald is acknowledged as one of the most desirable gemstones, and aquamarine has recently sustained an unprecedented rise in price. Morganite has s...
Beryllonite View Profile
Beryllonite is really not suited for wear, and since it is available only as small colorless stones, there is not much incentive to make jewelry out of it. However, Beryllonite is one of the truly rare collector gems and should be greatly prized as a cut stone. The cleavage makes gems hard to cut.
Bismutotantalite View Profile
Extremely rare as a cut gem, even in very complete collections. Manu of the minerals in the tantalite group have been faceted; bismutotantalite is perhaps the rarest of them all. The color is attractive, but low hardness and good cleavage make use in jewelry unadvisable.
Boleite View Profile
Cut boleite is strictly for collectors, since it is soft and very rare. Faceted gems of any transparency should be considered among the rarest of all gemstones. The color is so attractive that any available stones would be quickly snapped up by collectors.
Boracite View Profile
With light blue and green colors, no cleavage, and high hardness, boracite is an uncommon mineral. Unfortunately for jewelry lovers, faceted boracites are very rare.
Bornite View Profile
Bornite is suitable only for cabochons. The bronzy color rapidly tarnishes in air to a magnificent iridescent color display, mostly purple, but also with blue and green tones. Bornite is too soft and brittle for anything but a collector curiosity, although cabochons are quite attractive when they tarnish. The material is not rare, so cabochons have no great value beyond the effort o...
Brazilianite View Profile
Brazilianite's lovely green to yellow colors make it a must for gem collectors. Large faceted stones are often flawed, but smaller cut gems can make beautiful jewelry pieces.
Breithauptite View Profile
Breithauptite is a curiosity cut for collectors, although it could be worn with care in jewelry. The color is extremely lovely, a delicate reddish or violet with metallic luster that is both unique and attractive. Sometimes the reddish sulfide is veined with streaks of native silver or colorless gangue minerals, providing interesting patterning to the color. The material is not very...
Brookite View Profile
Brookite is a very dark-colored mineral, transparent only in small fragments. Cuttable crystals are exceedingly rare, and attractive-looking cut stones are among the rarest of all gems. Most stones are in private collections.
Brucite View Profile
Brucite is extremely difficult to cut, and only a few faceted stones in the ½-1 carat size range are known.
Bustamite View Profile
Bustamite is very similar in appearance and properties to rhodonite. The Japanese crystals are very rich in Mn. The color, when fresh, is paler than rhodonite. Bustamite may also be fibrous, and then yields fine catseye gems, but these are extremely rare. Faceted Bustamite are very attractive, especially in the pinkish shades, but stones over 1-2 carats are very rare collector items...
Calcite View Profile
Calcite is common and abundant throughout the world. The material has little intrinsic value since it is not scarce. However, calcite is one of the most difficult of all minerals to be cut because of perfect cleavage in 3 directions. The cost of faceted stone is therefore mostly in the labor of cutting. Normally, a faceted stone breaks during cutting, and the finished gem is much sm...
Canasite View Profile
The material usually seen on the market as “canasite” is purplish in color. It is frequently confused with another purplish material, a member of the serpentine family known as stichtite. However, stichtite occurs in elongated fibers that have a kind of lustrous sheen, almost asbestiform, whereas canasite is granular. Recent research seems to indicate that, in fact, the mate...
Cancrinite View Profile
Cancrinite is one of the most attractive of all opaque or translucent gem materials. It is a bit too soft for average wear, but its distinctive color is worthy of jewelry. Cancrinite may be tricky to cut because it often contains numerous hard inclusions. Faceted gems even as small as 1 carat are considered great rarities.
Carnelian View Profile
The best-known and generally least expensive variety of chalcedony is carnelian. It ranges in color from yellow-orange to rich, near reddish orange, to orangey brown, and varies from semi-opaque to highly translucent.
Cassiterite View Profile
Cassiterite has tremendous dispersive fire, much more than diamond, that is visible in properly cut pale-colored gems. This lighter-colored material is, however, very rare except in small fragments. Cassiterite is a fine gemstone – it is rather hard, and there is no cleavage problem. It is unfortunate that cuttable rough is so scarce. Cassiterites under 5 carats are not among the ...
Catapleiite View Profile
The only reported cut catapleiite is from Mte. Ste. Hilaire, Quebec, Canada, in the form of tiny colorless gems.
Celestite View Profile
Soft, fragile, and hard to cut, celestite or celestine is seldom seen in collections. These gems are usually colorless or pale blue, but rare orange, green, yellow, and red shades have also been found.
Ceruleite View Profile
A little-known gem material of truly exquisite color, sky-blue ceruleite takes a very high polish easily and quickly. However, fine, solid, cuttable pieces are extremely rare.
Cerussite View Profile
Cut cerussite is as beautiful as diamond since has higher dispersion, is usually free of any body color, and has an adamantine luster. However, cerussite is extremely soft and one of the most brittle and heat sensitive of all minerals. Cutting a gem is a major chore, and cutting a very large one without breaking it is almost impossible.
Chabazite View Profile
Although faceting chabazite isn't too difficult, it's too soft for jewelry. However, only a handful of cut chabazites may exist because facetable material is extremely scarce.
Chalcedony View Profile
Technically, chalcedony (kal SED' uh nee) is any form of microcrystalline or cryptocrystalline quartz, (meaning any form of quartz whose crystals are too small to be seen without high magnification.) In common practice, only the translucent, single color types are sold as "chalcedony" whereas the rest of this group are sold under individual variety names, or as jasper or agate. Whil...
Chambersite View Profile
Chambersite is an exceedingly rare mineral, as might be gathered from the locality information. Crystals are generally tiny and are recovered by skin diving to a depth of as much as 70 feet in brine. Cut stones are merely curiosities and very few exist.
Charoite View Profile
Named for the only locale in which it is found, the Charo River Valley in the former Soviet Union, Charoite is one of the few gems that is so distinctive in its color and patterns that a gemologist can feel justified in making a "sight" identification. There's really no other material likely to be mistaken for it -- at least this is true until a synthetic or man-made simulant comes ...
Chicken-Blood Stone View Profile
Chicken-Blood stone is one of the most prized ornamental materials in China. It is considered a protection from evil and is believed to be even more powerful than jade. In Chinese tradition, the color red is symbolic of good luck. Thus the Chinese give red seals, or chicken blood stone, to bless people for events such as marriages, birthdays, promotions, and success.
Childrenite View Profile
Cut childrenite is a great rarity, and all gems are small. Cut eosphorite is more abundantly available, though both materials are very scarce.
Chiolite View Profile
Chiolite makes a challenging gem. It's difficult to cut, extremely rare, and has little appeal. It's solely a curiosity in the gem world.
Chromite View Profile
Chromite is shiny and black, and makes a curious-looking cabochon with no special attraction. Occasionally, a cabochon has a reddish color. The stones have little value because the material is extremely abundant but are cut as curiosities only.
Chrysoberyl View Profile
Transparent chrysoberyl makes a handsome faceted gem and is one of the hardest and toughest for jewelry purposes. Cleavage is not distinct, and the hardness is near that of sapphire and ruby. In general, the bright yellow and yellow-green shades are the most desirable, but some of the browns are also striking and handsome. Properly cut gems are very brilliant, although they lack fir...
Chrysocolla View Profile
Chrysocolla often forms as a gel mixed with silica and hardens to a blue material that is basically a Chrysocolla-saturated quartz. This material is very hard (7), wears well, and is often seen in jewelry. Chrysocolla mixed with malachite is often sold asEilat Stone and comes from many localities; the color is blue to bluegreen, S.G. = 2.8-3.2.
Chrysoprase View Profile
Apple green chalcedony that derives its color from nickel is chrysoprase. Ranging from nearly opaque to nearly transparent, its color spectrum includes olivey, to nearly pure greens of medium tone.
Cinnabar View Profile
Magnificent red cinnabar is extremely soft and fragile, so faceted material is rare. It's cut primarily for collectors and carvings.
Citrine View Profile
Citrine, yellow to red-orange quartz, was once the Rodney Dangerfield of the gem world; its sheer abundance being responsible for this "no respect" treatment. That has begun to turn around somewhat in the last couple of decades as fashions have repeatedly emphasized earth tones and home shopping networks have marketed the various shades of citrine aggressively with catchy adjectives...
Cobaltite View Profile
Cabochons are interesting because of the lovely reddish metallic appearance of this mineral. Cut stones are infrequently seen and are cut only as a curiosity by the collector who wants to have one of everything.
Colemanite View Profile
Colemanite is cut only as a curiosity, since it has no attractive colors. Faceted gems are normally colorless, have a low dispersion (no fire) and are brittle and fragile as well as difficult to cut. They have no appeal except to collectors of the unusual, and material for cutting is potentially abundantly available, since transparent material is not extremely rare.
Color Change Garnet View Profile
Color change garnets are mostly pyrope and spessartite in composition. Except for the color change, they are identical in properties to the Malaia variety. Their primary source is Africa.
Coral View Profile
Coral is the axial skeleton of an animal called the coral polyp, a tiny (1 mm), almost plantlike animal that lives in warm oceans (13-16°C). The solid material we know as coral is the colony in which these tiny animals live. Coral is often branched and treelike.
Cordierite View Profile
The crystal structure of cordierite has many similarities to that of beryl; indialite, the dimorph, in fact has the same structure as beryl. Iolite with hematite inclusions (bloodshot iolite) comes from Sri Lanka. The inclusions sometimes yield a gem showing a 4-rayed star (quite rare). The blue color of iolite along one optical direction strongly resembles sapphire, and such gems, ...
Corundum View Profile
Next to diamond, corundum is the hardest mineral known and is very compact and dense, with no cleavage. As a result, corundum is one of the best of all jewelry stones, especially star corundum, which is tough as well as scratch-resistant. Faceted gems are slightly brittle and can be chipped, though much less easily than other gems. Ruby is red corundum. All other colors of corundu...
Covellite View Profile
Although covellite has attractive blue colors and shows iridescence, this rare mineral is difficult to cut. You can scratch it with a fingernail! As cut gems, they're strictly curiosities for collectors.
Creedite View Profile
Creedite is one of the very rare minerals known to collectors. It may well be that less than a dozen creedite gems have ever been cut. The mineral itself is rare, cuttable crystals even more so. These would be colorless or purple and from the Mexican occurrence. The hardness is too low for wear - strictly a collector gem.
Crocoite View Profile
Lovely saffron-colored crocoite is quite a rare mineral. Although too soft and brittle for jewelry wear, a few crystals have been faceted for collectors.
Cryolite View Profile
Cut cryolite is somewhat translucent, and has a "sleepy" look. The cuttable material has a very low birefringence, is colorless, and very soft—not exactly an exciting-looking gem. However, there are very few cut stones in existence because of the extreme scarcity of suitable rough. In addition, cryolite is only found abundantly at one locality (Ivigtut).
Cuprite View Profile
Cuprite is one of the rarest of all gems. For all practical purposes, cuttable material comes from only one locality. Only good crystals or pieces of crystals are cuttable, however, as other material from this mine is opaque. Mineral collectors do not wish to see their fine crystals cut, limiting the supply of available faceting material. Cut gems have a metallic appearance and magn...
Danburite View Profile
A hard and durable gemstone, danburite is an excellent choice for jewelry wear. Although the mineral isn't rare, large facetable pieces are scarce.
Datolite View Profile
Datolite is a rather soft gemstone if wear is considered. The nodules come in very attractive colors. Faceted stones are extremely brilliant, though their dispersion (fire) is low. Most faceted gems are colorless, pale yellowish or pale green.
Demantoid Garnet View Profile
Demantoid is a green colored variety of andradite which is a variety of garnet group of minerals.
Diamond View Profile
Diamond is the most romanticized and heavily marketed of all gemstones. Nearly every jewelry establishment handles diamonds, even if it has no other gemstones in stock. The annual world production of diamonds is on the order of 10 tons. Of course, only a small percentage of this is gem quality, but diamond of very fine quality is nowhere near as scarce as equivalently high quality r...
Diaspore View Profile
Diaspore is hard enough to make a durable jewelry stone, but the typical light brownish color is not easy to sell. Despite the large Turkish material, this is a very rare gemstone indeed.
Dickinsonite View Profile
This mineral is seldom even mentioned in the gem literature because it is so rare and has been so seldom cut. Faceted gems are practically nonexistent, and would be among the rarest of all cut stones.
Diopside View Profile
Violane has been used for beads and inlay—transparent material is always very tiny. The color of this material is deep violet or blue and is very rare. Catseye material cuts extremely sharp eyes, the best being from Burma. Faceted diopside is not extremely rare, but large (over 15 carats) clean stones are. Colors are usually dark, so a bright and attractive gem is most desirable. ...
Dioptase View Profile
Dioptase is abundant in mineral collections throughout the world and is not considered a great rarity, but faceted gems are extremely rare due to a paucity of clean fragments. Clean stones over 1 carat are virtually nonexistent, and few collections have stones at all. Cabochons are blue-green, translucent, and quite attractive but are much too soft for wear.
Dolomite View Profile
Dolomite is a rarely seen gem with distinctive Birefringence (as a carbonate) but is too soft and fragile for wear Spanish crystals are widely sold to collectors so transparent material is fairly abundant.
Dumortierite View Profile
Dumortierite is a beautiful and very hard material, eminently suitable for jewelry. The cabochon material is the only generally known form, since faceted stones are so rare. Fibrous inclusions have been noted in the transparent Brazilian stones.
Ekanite View Profile
Ekanite is metamict as a result of the U and Th content. The properties vary, depending on the degree of breakdown of the structure. Ekanite is one of the very rarest of all gems, and only a few are known. More undoubtedly exist that have been sold as other Sri Lankan gems, but the total number of gems is a mere handful.
Emerald View Profile
Since the time of Cleopatra, emeralds have epitomized the color of green gemstones. It would be easy to question this statement if all one had seen of emeralds were the commercial, (and poorer,) quality stones which abound on home shopping networks and in some jewelry stores.
Enstatite View Profile
Most gem enstatites have indices in the range 1.663-1.673. The brown and green gems from Tanzania are enstatites, as are the brownish-green stones from Sri Lanka. Green and brown gems from India and Brazil tend to be in the bronzite composition range. The gems of the orthopyroxene series are usually very dark, slightly brittle because of cleavage, and generally not appealing for jew...
Eosphorite View Profile
Pink gems are extremely attractive when cut, especially as round brilliants. The hardness makes wear unrecommended; cutting presents no great problems. This is a very rare gemstone, seen only in a few collections.
Epidote View Profile
The epidote minerals are very interesting and span a wide range of the gem market. Hancockite, from New Jersey is very rare, and if a faceted gem exists it would be extremely small (under 1-2 carats).
Ettringite View Profile
Ettringite is not generally facetable; any cut stone would be considered an extreme rarity. South African material has yielded minute stones, some of which may have been labeled sturmanite.
Euclase View Profile
Euclase is a hard enough gem to be worn safely in jewelry. It may not be terribly exciting to look at (if colorless), but the colored gems are truly beautiful and exceedingly rare over a few carats in size. These gems can be very brilliant. The cleavage makes cutting a bit tricky.
Eudialyte View Profile
Although cabochons could be cut from massive eudialite or translucent crystals, transparent material suitable for faceting is elusive and always small.
Euxenite View Profile
Euxenite is seldom seen in collections. Most collectors would not regard the mineral as facetable, but transparent fragments and areas of crystals have been noted that could cut small gems. Sometimes cabochons are cut by collectors, but these are not very striking. The colors of faceted stones would be too dark to make them appealing.
Feldspar View Profile
Feldspars are the most common minerals at the Earth's surface. In fact, if the entire composition of the Earth's crust were regarded as a single mineral, it would calculate out almost exactly as a feldspar.
Fergusonite View Profile
This mineral is not abundant and is known from various localities. Cabochons are cut merely as curiosities, as they have no special features that would recommend them except rarity. There are reports of transparent grains or parts of crystals that have been cut by collectors, but these are merely curiosities and are seldom encountered.
Fluorite View Profile
Fluorite is too fragile for wear because of its cleavage and brittleness. It is also on the soft side for jewelry use. Fluorite does, however, occur in a very wide range of attractive colors. Faceted gems can be extremely bright, despite the low index of refraction, since the material takes a high polish. Most of the available stones are in the blue-violet-green range; pinks are rar...
Freshwater Pearls View Profile
Pearls are unique among gemstones, being the only ones found within a living creature and the only ones that requires no fashioning, (cutting or polishing,) before use. Another distinctive feature is its near exclusive use by one gender. Although some efforts have been made to market pearl jewelry to males in recent years, pearls remain the most "feminine" of all gemstones. Designat...
Friedelite View Profile
Friedelite is not abundant, and gem-quality material is rarely seen even in large collections. Faceted gems are true collector's items.
Gadolinite View Profile
This is not a terribly attractive gemstone, but faceted gems would be a tremendous rarity. The material is quite brittle, but there is no cleavage to cause problems in cutting. I do not know of the existence of a faceted gem at this writing.
Garnet View Profile
Garnet comes from the Latin word, granatus which means grain. That is because many garnet deposits are small grains of red crystals in or on their host rock.
Gaylussite View Profile
This mineral is very hard to cut because of extreme softness and cleavage. Gaylussite dries out slowly in air and the surfaces may turn white. Stones in collections are therefore best stored in sealed containers to prevent dehydration. Gaylussite is seen only in very comprehensive collections, and relatively few stones have been cut. Transparent crystals are not terribly rare, but f...
Grandidierite View Profile
Grandidierite is a rather rare mineral, with a lovely blue-green color. It is never transparent enough to facet, but attractive, sometimes even jadelike cabochons are cuttable from the translucent material. The high hardness makes it suitable for wear, although cutters have to pay close attention to the cleavage. Cut grandidierite is seldom seen in collections because few collectors...
Gypsum View Profile
Gypsum is one of the most abundant minerals and is found especially in evaporite environments. Alabaster, the massive, granular variety, has been used for thousands of years, made into vases, bowls, and other useful and decorative objects. Today it is used in ashtrays, clock housings, paperweights, and so forth.
Hambergite View Profile
Although hard enough for jewelry use, rare hambergite is a gem for collectors of the unusual. Its combination of high birefringence and very low specific gravity makes it easy to identify.
Haϋyne View Profile
Haϋyne is one of the major constituents of lapis lazuli, a well-known and ancient gem material. It is, however, rarely seen as a distinct gem species. It is cut for collectors mainly as a curiosity, but faceted gems that are deep blue in color are extremely beautiful. Blue is the most sought after color in this material.
Heliodor View Profile
An overview on Heliodor Jewelry and Gemstones.Covers details and essential information on the physical properties and characteristics of Heliodor gemstones.
Hematite View Profile
Hematite was used by the American Indians and others as a face paint (so-called red ochre). The polishing compound known as rouge, used widely on silver and gold, is powdered hematite. The streak is characteristic and diagnostic. Hematite is a weak electrical conductor, as opposed to psilomelane, a similar appearing manganese oxide. Much hematite is cut in Idar-Oberstein, Germany,...
Hemimorphite View Profile
Massive hemimorphite can have a very delicate, blue color. However, it's seldom cut because not very much has appeared on the market.
Herderite View Profile
Herderite is a rare collector's gem, especially in larger sizes. It's too soft for wear but attractive when cut and can show a wide range of colors.
Hessonite View Profile
Hessonite is a red to orange/yellow colored variety of grossular which is a variety of garnet.
Hodgkinsonite View Profile
Hodgkinsonite is one of the rarest of all collector gems. Cut stones are bright and richly colored, but the crystals were never abundant and still fewer had transparent areas. Fewer than 10 cut stones may exist.
Holtite View Profile
This mineral was first noted in 1937 but was not described in detail until 1971. It has not yet been seen as a gem, but the high hardness would allow it be worn with no risk of scratching. Holtite is now considered to be a variety of dumortierite. The mineral comes from the one locality, and a cut stone would have to be considered a great rarity.
Howlite View Profile
Howlite is always opaque in nodules; it is an abundant material and easy to acquire. Sometimes it contains black, threadlike impurities resembling the veining in turquoise. Howlite is frequently dyed blue to resemble turquoise, and it makes a most convincing simulant. The white material is relatively unexciting in appearance.
Huebnerite View Profile
It should not be difficult to find numerous small faceted huebnerites among larger gemstone collections. Certainly ample material exists to cut a number of such gems, although they are rarely offered for sale.
Humite View Profile
Faceted chondrodite is almost unknown, a pity since the color is very rich and the material is hard and durable enough for wear. Cutting presents no great difficulty, but rough is virtually unobtainable, and only tiny stones could be produced. The same is true for norbergite and humite. The exception seems to be clinohumite from the Pamir Mountains in the USSR. Crystals occur there ...
Hureaulite View Profile
Hureaulite can show rich and lively pink, rose, and orange colors. However, this collector's gem is rarely cut.
Hydrogrossular View Profile
Hydrogrossular differs from the other garnets in that it is never transparent. It ranges from translucent to opaque. The most common color is a bluish green, but they are also found in pink, white, and gray.
Hyperitdiabas View Profile
Hyperitdiabas is one of the most outstanding minerals I have encountered in recent years. Its appearance striking beautiful and a close inspection reveals still more delights. It has all the properties of a commercially important gemstone, but its rarity will keep it on the sidelines.
Idocrase View Profile
Idocrase is one of the lesser known and more beautiful collector gems. When properly cut it is as bright and attractive as the grossular garnets, which it so strongly resembles. The complexities of its chemistry lead to a huge range in properties and colors. Cuttable material is known from Italy (brown and green), Quebec (pale green, bright yellow), New York (brown), Pakistan (gree...
Inderite View Profile
Inderite is very soft and difficult to cut, and only a few stones have been cut by hobbyists. There is plenty of cuttable material in existence, and although the material comes from only a few localities, it is not considered a great rarity. The surface of cut stones may become white and cloudy after cutting; care must be taken in storage and to dry the stones after cutting.
Iolite View Profile
This stone, which represents one of the few relatively available and affordable blue stone options, is rapidly gaining in popularity. Arguably the gain is due more to exposure in mail order catalogs and on cable shopping channels than to promotion by traditional jewelry stores. Run of the mill stones often have a steely, inky or washed out blue color, but the best specimens can riva...
Jadeite View Profile
Jadeite is usually marketed through Yunan Province, China. Green boulders may have a brown skin due to weathering, which is often utilized in carving. The best jade known is Burmese in origin and occurs in a wide range of colors. There are many simulants and imitations. Imperial jade is exceedingly rare and very costly. Another popular color is a fine apple green shade, as well a...
Jeremejevite View Profile
Until the Namibian material was found, jeremejevite was an exceedingly rare mineral available only in microscopic grains. The African crystals are amazing in being both large and gemmy. Few gems have been cut from the material since the crystals are prized by collectors and the extent of the find is unknown. The crystals are not abundant at the locality, so jeremejevite will remain ...
Jet View Profile
Historically a popular black gem, jet has declined in popularity in modern times. Although jet jewelry has been long associated with mourning, this organic gem can be made into large, eye-catching beads, carvings, and even faceted pieces.
Kämmererite View Profile
Kämmererite is a beautiful but rare mineral. It is micaceous; consequently, it is extraordinarily difficult to facet, which has severely limited the availability of cut gems. It would have to be handled with great care to avoid cleaving. A few clean, well-cut gems do Perfect basal cleavage; micaceous; laminae exist, nonetheless, a testimony to the perseverance of hobbyists!
Kornerupine View Profile
Star kornerupine also has been found I(Mogok, Burma) but is very rare. Kornerupine is generally dark brown or green and not very attractive due to the somber colors. The light green material from Kenya is much more appealing, but the sizes are always small (under 3 carats as a rule). The color is caused by traces of Fe, Cr. and V. Despite the fact that many stones are in museums a...
Kurnakovite View Profile
Kurnakovite is similar to inderite. Both are colorless and very uninteresting as faceted gems, which is why very few have been cut. The material is obtainable in large size, but softness and cleavage make cutting a real chore.
Kyanite View Profile
Kyanite is very rare as a faceted gem, especially if free from inclusions and flaws. The material is extremely difficult to cut because of its perfect cleavage and the extreme variability in hardness in different directions in the same crystal. A few catseye kyanites are known to exist.
Labradorite View Profile
An overview on Labradorite Jewelry and Gemstones. Covers details and essential information on the physical properties and characteristics of Labradorite.
Langbeinite View Profile
This material is nondescript and is cut solely as a curiosity. The gems are soft, pale colored, or colorless, with no fire. Few cut stones have been reported, but this may be due to a lack of interest rather than a lack of suitable rough.
Lapis Lazuli View Profile
The gem known as lapis lazuli, or simply lapis, is actually a rock, composed of lazurite, hauyne. sodalite, and nosean, all members of the sodalite group of minerals. Lazurite itself may be considered a sulfurrich hauyne. Calcite and pyrite in various percentages are also present in the rock. The finest lapis is considered to be a solid, deep blue with no white calcite spots and jus...
Lawsonite View Profile
Lawsonite is extremely rare as a faceted stone, seldom reported and generally unavailable.
Lazulite View Profile
Lazulite makes a magnificent, deep blue gemstone. Although the mineral itself occurs widely, gem-quality rough is limited. Specimens are prized by collectors but can also be faceted with care or cut into cabochons for jewelry.
Legrandite View Profile
This mineral was first described in 1932, and it has become a very popular specimen mineral with collectors because of its intense yellow color and esthetic crystal groupings. It is too soft for wear, but the yellow color is unique among gems and very distinctive. This is one of the loveliest of all the rare collector gemstones.
Lepidolite View Profile
Reddish granular or massive lepidolite is usually slabbed for ornamental purposes, such as ashtrays paperweights, and bookends. Faceted micas are virtually nonexistent because of the perfection of the cleavage and the variable hardness within crystals.
Leucite View Profile
Leucite is abundant in various lava rocks but is extremely rare in facetable crystals. The material has little appeal except for its extreme scarcity. Stones often have a slight milky or cloudy look, and anything over 3 carats is likely to be included.
Linarite View Profile
The blue color of linarite is magnificent, and it is a pity that large facetable rough has not been found. Clean areas of crystals are usually very small, and breakage in cutting due to the softness and cleavage of the mineral further complicates the salvaging of a large gem. This is a lovely collector item and an extremely rare one.
Ludlamite View Profile
Ludlamite has a lovely green color but is too soft for wear. Large crystals are known from only a few localities, and cut stones are extremely rare.
Magnesite View Profile
Gems of completely transparent magnesite are both rare and beautiful. The huge birefringence is obvious even in small stones, and larger gems have a sleepy look, or fuzziness, due to the doubling of back facets as seen through the table. Faceted magnesite is rarely seen, and the material is relatively difficult to cut. Facetable crystals come only from Brazil.
Malachite View Profile
Malachite is one of the most popular and beautiful of decorative stones. lts rich, patterned coloration in shades of green is unique among gems. Malachite can (with great care) be turned on a lathe to make goblets and candlesticks. It is extensively used to make cabochons, beads, boxes, and carvings of all kinds. Fibrous aggregates are packed masses of crystals, and these also take ...
Malaya or Malaia Garnet View Profile
Malaia garnet is a variety of garnet that is typically light to dark slightly pinkish orange, reddish orange, or yellowish orange in color.
Mali Garnet View Profile
Mali Garnet, one of the rarer varieties within the garnet group, is a mixture of the species grossular and andradite, (therefore it is sometimes called "grandite.") The entire garnet group is a solid solution series of silicates. That means the crystal structure is basically the same throughout the group, but some of the chemical formulas differ. At certain key points throughout the...
Manganotantalite View Profile
Manganotantalite makes a spectacular red brown gem that is a very rare collector’s item. Transparent material is light enough in color to allow lots of light to enter and leave a cut gem, and properly cut stones are lively and brilliant. Cutting is difficult because of the cleavage.
Marcasite View Profile
Marcasite has a long history of use as a decorative and jewelry material. However, this brassy colored, metallic stone is quite brittle and seldom seen in modern jewelry.
Meliphanite View Profile
Meliphanite is an extremely rare gemstone, and perhaps fewer than 5-10 faceted stones have ever been cut.
Mellite View Profile
Mellite is one of the most unusual of all gems, being an organic material formed by inorganic processes, just the reverse of the situation with pearls and coral. Crystals are additionally unusual in being pyroelectric (they generate an electric current when heated). Mellite is soft and very fragile. but is quite beautiful when cut. Truly this is one of the most interesting of the ra...
Microcline View Profile
Microcline is a variety of feldspar. The only microcline you are likely to encounter is amazonite.
Microlite View Profile
Ranging in color from pale yellow to brown, reddish, and green, microlite cabochons are prized by collectors. Faceted gems are very beautiful but extremely rare.
Milarite View Profile
Milarite was originally known as a green mineral, until fine yellow crystals were discovered in Mexico in 1968. Larger Mexican crystals have transparent areas and have been faceted into small gems of pleasant appearance but great rarity.
Millerite View Profile
Massive millerite is sometimes cut into a cabochon by a collector or sliced into slabs for decorative purposes. The yellow color is very rich and attractive, and the cut gems are indeed curiosities. The mineral is too soft for wear. Massive millerite is of no great interest to mineral collectors and therefore might be difficult to obtain in the marketplace, although it is abundant a...
Mimetite View Profile
Faceted mimetite is one of the rarest of all gems since only one pocket of transparent crystals has ever been found (at Tsumeb), and few of these crystals have been cut. Orange and yellow cabochons are richly colored but are too soft for wear.
Moldavite View Profile
Moldavite is a transparent to translucent olive to bottle green tektite, first found in 1787 at the Moldau River in Czechoslovakia. In general, tektites are natural glasses which are thought to have been created by melting of silica sand or rock by meteoric impact. A popular idea is that the melted material then was flung into the air and cooled into glass as it landed over the area...
Monazite View Profile
Monazite may be partially metamict, with N=1.79. Stones can be an attractive yellow or brown color but are usually small.
Moonstone View Profile
Moonstone or "Adularia", an orthoclase feldspar, was originally named for an early mining site at Mt. Adular in Switzerland. From this tradition we derive the term "adularescence" which is the optical phenomenon of iridescence which creates a billowy, floating blue to white light in this gem. Adularescence is due to diffraction of light as it hits thin, alternating layers of orthocl...
Mordenite View Profile
Compact, fibrous material is cabbed because the fibers provide a chatoyancy that sometimes yields weak catseyes. Coloration in the material is due to staining. This is a relatively unexciting mineral, and gems are equally uninspiring. Nevertheless, it has been reported as being cut for collectors.
Morganite View Profile
A member of the beryl family, morganite shows a range of pink colors due to traces of manganese. Recently, this gemstone has seen an increase in popularity and value. Like most beryls, morganite makes an excellent jewelry stone.
Nambulite View Profile
The color of Namibian nambulite is a striking orange-red, very intense, and not really like any other gem I have seen. Cut stones would be both extremely rare and quite magnificent, perhaps bearing some similarities to rhodonite.
Nepheline View Profile
A variety called elaeolite is red, green, brown, or gray, massive or in crystals filled with minute inclusions. These inclusions produce a sheen that yields a catseye effect in cabochons. Facetable nepheline is a great rarity, and very few gems have been cut, always in the 1-2 carat range or smaller.
Nephrite Jade View Profile
Nephrite is one of the two distinct minerals commonly known as jade. While nephrite doesn't match the variety or the fine green colors found in jadeite, it's even more durable as a gem material for jewelry and carved objects.
Neptunite View Profile
An overview on Neptunite Jewelry and Gemstones. Covers details and essential information on the physical properties and characteristics of Neptunite gems.
Niccolite View Profile
Niccolite is always cut as cabochons. The color is a delicate peachy red and is extremely beautiful, especially in polished material. The metallic luster combined with this unusual color is very distinctive. Niccolite is hard enough to be worn on bola ties and pendants. It sometimes tarnishes to a darker color, but a coat of clear nail polish may prevent this.
Obsidian View Profile
Obsidian is an attractive material and displays a wide variety of appearances. Snowflake obsidian, with spherulites of cristobalite, is widely used in jewelry as beads and cabochons. Apache tears, which are cores of unaltered glass in nodular shells of decomposed obsidian, are popular among beginning hobbyists. Some of these have been faceted. Green, blue, and reddish (transparent...
Opal View Profile
Opals stand in a class by themselves. More than any other gem, each opal is distinctly an individual. No other stone has as rich and varied folklore. They are both one of the luckiest and unluckiest gems a person can own. They are so unique, they have their own descriptive vocabulary. Opals are also the most delicate gems commonly worn. They require special care to insure their hea...
Oregon Sunstone View Profile
What a nice coincidence that Lapidary Journal's cover story for January, 1998 is on Oregon Sunstone! The article points out that prior to the finds of substantial amounts of facetable crystals in Oregon, most sunstone, much of which came from the Orient, was used for cabbing material, or in the production of pale yellow, low value, faceted goods. Such is the case no more. An incredi...
Orthoclase View Profile
Orthoclase is best known for moonstone. It is occasionally a transparent, faceted gem. Note that moonstone is occasionally a labradorite.
Painite View Profile
No cut gems are known. The first discovered specimen is the red crystal in the British Museum in London, weighing 1.7 grams. The color resembles garnet, and the density is that of garnet or ruby. This means that there might be cut gems in existence that have been mis-identified as ruby or garnet. The refractive indices are unlike those for ruby, and the material is so clearly birefr...
Palygorskite View Profile
Although marketed as “angel skin opal,” “rock wood,” and “mountain leather,” palygorskite is neither opal, wood, nor leather. This unusual, parchment-like mineral can be cut into cabochons or carved.
Papagoite View Profile
An overview on Papagoite Jewelry and Gemstones. Covers details and essential information on the physical properties and characteristics of Papagoite gems.
Pargasite View Profile
The amphibole group is very large and extremely complex and contains numerous distinct species that vary subtly in chemistry and physical properties. Pargasite and ferropargasite are calcic amphiboles that generally are lumped together as hornblende,even though up to 16 distinct minerals belong to this group, including actinolite. The identity of a specific amphibole is determined ...
Parisite View Profile
An overview on Parisite Jewelry and Gemstones. Covers details and essential information on the physical properties and characteristics of Parisite gemstones
Pearl View Profile
An overview on Pearl Jewelry and Gemstones. Covers details and essential information on the physical properties and characteristics of Pearl gemstones.
Pectolite (Larimar) View Profile
Fibrous pectolite has long been a curiosity for gem collectors. Compact material can make wonderful cabochons, and transparent crystals are rare and usually tiny. Larimar, blue pectolite from the Dominican Republic, has become a popular jewelry stone.
Pentlandite View Profile
Pentlandite resembles other yellowish metallic minerals and is cut by collectors as a curiosity. The cut stones are quite attractive but too soft for hard wear.
Periclase View Profile
Periclase has been synthesized in large masses in the laboratory, but these have no market significance. A faceted natural periclase would be a great rarity due to the extreme scarcity of suitable faceting rough. The expected size would be less than 1 carat.
Peridot View Profile
To my mind, peridot is an under appreciated gemstone. Perhaps this has become the case due to the public's familiarity with low quality, olivey material which is inadequately cut and polished. Admittedly it can look pretty awful, but the lime and apple green stones given custom cuts and polishes are something else again.
Peristerite View Profile
Peristerite is primarily oligoclase with a complex mixture of feldspars. It has iridescence that is either blue or white.
Perthite View Profile
Perthite is a blend of microcline, albite and oligoclase. It is usually brown and white. May have gold or white iridescence.
Petalite View Profile
Gem-quality, colorless, facetable petalite is rare and desirable to collectors. More so if the stones are large and free of inclusions.
Phenakite View Profile
Rare phenakite is a very hard gem material suitable for jewelry. Usually colorless, cut stones have little fire but can be very bright.
Phosgenite View Profile
Massive material can be cut into interesting cabochons of various colors, up to the size of the rough (several inches). Phosgenite is too soft to wear. The strong fluorescence is of interest to specialists in fluorescent minerals.
Phosphophyllite View Profile
Phosphophyllite possesses a color almost unique in gems, a lovely blue-green shade enhanced by cutting. This is a very rare mineral. Stones are seldom available because of lack of incentive to cut up good crystals. Few large stones exist; the material is quite brittle and fragile and very difficult to cut, with an easily developed cleavage. This is one of the more desirable of the c...
Pollucite View Profile
Colorless pollucites lack fire when cut and are usually small. However, this very rare cesium mineral is a coveted collector's gem.
Powellite View Profile
An overview on Powellite Jewelry and Gems. Covers details and essential information on the physical properties and characteristics of Powellite gemstones.
Prehnite View Profile
Prehnite is popular as a cabochon material among hobbyists because of its lovely green and blue-green to yellow colors. Completely transparent material is extremely rare but might be found in crystals from Asbestos, Quebec. Yellowish to greenish translucent material from Australia has been faceted and makes a striking cut gemstone with a rich color and interesting appearance, with a...
Prosopite View Profile
An overview on Prosopite Jewelry and Gemstones. Covers details and essential information on the physical properties and characteristics of Prosopite gems.
Proustite View Profile
Proustite crystals have magnificent red colors and good brilliance. Although facetable, they're too soft for jewelry use but highly desired as collector's gems.
Pumpellyite View Profile
The gem variety of pumpellyite, chlorastrolite, is best known from the Lake Superior district of the United States. It typically forms aggregates of packed fibers that are mixed with other minerals, resulting in a green and white pattern reminiscent of tortoise shell. The effect is best observed when the fibers are in radial clusters that yield circular markings.
Purpurite View Profile
This material is never transparent and is too soft for wear. However, cabochons are a magnificent purplish rose hues that have essentially no counterpart in the gem world. The material is available from Namibia in abundance and at low cost.
Pyrargyrite View Profile
Pyrargyrite is found in a number of localities in well-formed crystals, but these are usually small. However, larger, transparent crystals from Bolivia and Chile have provided a limited amount of cuttable rough. Stones approaching 50 carats have been cut, but these tend to be too dark to be really attractive. They are exceedingly rare, however, since pyrargyrite is seldom transparen...
Pyrite View Profile
Pyrite is more commonly known as fool’s gold and is familiar to nearly every mineral collector. It has been used for centuries both in jewelry and as an ore of iron. “Marcasite” stones in jewelry are frequently pyrite, since the latter is more stable. The material is very brittle and heat sensitive and requires some care in cutting. Cabochons are sometimes cut, but they have...
Pyrope View Profile
Pyrope comes from a Greek word meaning fire like. The common dark red garnets are a mixture of pyrope and almandine.
Pyrophyllite View Profile
Pyrophyllite resembles talc in many ways and is indistinguishable by eye from soapstone. Chemical tests are needed to distinguish them. North Carolina material is often used in carvings, as is the material from China known as agalmatolite.
Pyroxmangite View Profile
Pyroxmangite is a very rare gemstone; grains are seldom clean enough to facet. The material resembles rhodonite and bustamite to a certain degree but can be distinguished on the basis of optic sign and birefringence. Faceted gems are hard to cut because of the cleavages, but once completed they are extremely beautiful and rich in color.
Pyrrohotite View Profile
An overview on Pyrrhotite Jewelry and Gemstones. Covers details and essential information on the physical properties and characteristics of Pyrrhotite gems.
Quartz View Profile
An overview on Quartz Jewelry and Gemstones. Covers details and essential information on the physical properties and characteristics of a Quartz mineral.
Realgar View Profile
Although this common arsenic sulfide mineral occurs worldwide, cut gem-quality realgar is extremely rare. This fine, red stone is very fragile, difficult to cut, and nearly impossible to wear.
Red Beryl View Profile
Discovered in 1904 and still found in gem quality at only one site in the world, the Wah-Wah Mountains of Utah, red beryl, or bixbite, is one of the world's rarest and most desirable gemstones. Typically as included as its fellow beryl, emerald, few crystals approach gem quality. Most specimens of fine crystals are zealously guarded by mineral collectors and are never faceted.
Rhodizite View Profile
Rhodizite is tough enough to make an excellent jewelry stone. However, it's quite a rare mineral. Faceted specimens are extremely rare and usually small and pale in color.
Rhodochrosite View Profile
Rhodochrosite is very rare in faceted form. The specimens are in such demand among mineral collectors that it would be an outrage to most to cut up a good crystal. Hotazel gems of large size have been available, but larger clean stones are very scarce and expensive. Colorado pink rhodochrosite in clean gems is also expensive and anything over 2-4 carats is considered very large. Arg...
Rhodonite View Profile
Ranging in color from pink to a fine rose red, rhodonite is a popular material for jewelry and decorative objects. Faceted rhodonite has an intense, beautiful color, but this material has a reputation as one of the most difficult gemstones to cut.
Rubellite Tourmaline View Profile
Rubellites are tourmalines with reasonably saturated dark pink to red colors and medium to dark tones. They make excellent jewelry stones, and ruby-red colored specimens without orange or brown overtones are highly prized.
Ruby View Profile
Ruby is red corundum, all other color varieties of corundum being referred to as sapphire. The name "Ruby" is from Latin - ruber - and is based on the gem's red color. That fact notwithstanding, the ruby color range includes pinkish, purplish, orangey, and brownish red depending on the chromium and iron content of the stone. The trace mineral content tends to vary with the geol...
Rutile View Profile
Though perhaps best known as inclusions within other gems, rutile crystals themselves can be faceted or cabbed as curiosities for collectors. Synthetics can show a variety of colors and have even been used as diamond simulants.
Saltwater Pearls View Profile
Pearls are one of our most ancient gems with records of commercial harvesting going back 2500 years. Their natural occurrence is very rare, with only one in several million shellfish ever producing a pearl. Oysters are the best-known source, but clams, mussels, and abalone also produce pearls.
Samarskite View Profile
Samarskite is a very heavy material from which lustrous black to brownish cabochons are sometimes cut as curiosities. The material is rather brittle and is not intended for wear. It is rarely seen or displayed since black stones are not terribly attractive. Sometimes a stone is faceted in the nature of jet or marcasite.
Sapphirine View Profile
An overview on Sapphirine Jewelry and Gemstones. Covers details and essential information on the physical properties and characteristics of Sapphirine gems.
Scapolite View Profile
This gem, which is not widely available and little recognized by the public, is none the less, a desirable and attractive gem material for jewelers as well as collectors. It is known mineralogically as Wernerite, after its discoverer. Similar to the gems in the garnet group, this gem ranges in color and precise gemological values along a "solution series" as the amount of sodium and...
Scorodite View Profile
Gems of scorodite are extremely rare (usually Tsumeb), but cut stones have a lovely color and intense pleochroism. Too soft to wear, the stone is suited for collectors of the rare and unusual.
Sellaite View Profile
An overview on Sellaite Jewelry and Gemstones. Covers details and essential information on the physical properties and characteristics of Sellaite gems.
Senarmontite View Profile
Senarmontite is a rare mineral, restricted in occurrence to the presence of antimony sulfide ores. It is much too soft to wear, and the colors are usually nondescript. However, a faceted senarmontite in any size would be a great rarity.
Serandite View Profile
This essentially is another one locality mineral, where very small gems have been cut from an occasional crystal fragment that is not always even transparent.
Serpentine View Profile
Bowenite is usually blue-green, yellow-green, or dark green and translucent; it is used for carving, knife handles, and so forth, and in jewelry. Williamsite contains dark octahedral crystals of chromite, and patches of white brucite (magnesium hydroxide).Ricolite is a banded serpentine from Rico, New Mexico. Satelile is a serpentine pseudomorph after asbestiform tremolite from...
Shattuckite View Profile
Shattuckite is often mixed with quartz, and data often reported for properties may be erroneous. The cabochons are rich blue in color and very popular, but the material is not abundant and seldom seen on the market.
Shortite View Profile
Shortite is an exceedingly rare, not overly attractive mineral. Cut gems are among the rarest of all faceted stones. The material is a carbonate and is therefore fragile and soft.
Siderite View Profile
Siderite is a difficult stone to facet, but cut gems of great beauty have been fashioned, especially from Portuguese rough.
Sillimanite View Profile
The fibrolite from Burma and Sri Lanka is well known to gem collectors, and highly prized because of its great scarcity. Blue and greenish gems are lovely, although very difficult to cut. Chatoyant material sometimes yields catseye fibrolites, which are also very rare. The material from Kenya is just as attractive as Burmese fibrolite but seems to be somewhat smaller in size.
Simpsonite View Profile
Simpsonite is an extremely rare gemstone. The material from Western Australia is bright yellow-orange and very beautiful. The mineral is hard and durable, with no cleavage, and could easily become a popular gemstone if it were more abundant. Gems over 1 carat should be considered extremely rare because clean material is a very small percentage of the limited supply of simpsonite tha...
Sinhalite View Profile
Long thought to be brown peridot, sinhalite was investigated in 1952 and found to be a new mineral. When cut, it is richly colored, bright, and attractive, and resembles citrine, peridot, or zircon. Large gems are very rare, but smaller stones are available in the marketplace. Some people have reported that it was easier at times to find a large sinhalite for sale than a small one, ...
Smaltite View Profile
Smaltite is a collectors oddity, cut only as cabochons. It is seldom seen in collections since it is not especially distinctive, with a color resembling other metallic sulfides and arsenides.
Smithsonite View Profile
The blue-green smithsonite from New Mexico has been popular with collectors for many years. Pinkish colors are due to cobalt, yellow to cadmium. The low hardness of smithsonite makes it unsuited for jewelry, but properly cut faceted gems are magnificent. The dispersion is almost as high as diamond, and faceted stones have both rich color and lots of fire. Among the most beautiful ar...
Sodalite View Profile
Tough, easy to cut or carve, and rich in color, typically blue, sodalite is highly desired by hobbyists. Even stones that lack transparency make lovely faceted gems.
Sogdianite View Profile
Sogdianite is an extremely rare mineral, suitable for cabochons. The color is striking and the material is hard enough to take a good polish. It is usually mixed with other minerals, so the SG and hardness are variable. Chemical analysis may be required to differentiate sogdianite from sugilite, but the latter is far more abundant.
Spessartite Garnet View Profile
Spessartite is somewhat rare. As with the other garnets, it always occurs in a blend with other species. Gems with the highest spessartite content are a light orange. Those with an almandine content are reddish, to red brown in hue.
Sphalerite View Profile
Sphalerite is one of the most beautiful of all cut gems. It occurs in shades of green, yellow, orange, brown, and fiery red (all colors due to Fe) that are enhanced by faceting. The luster can be adamantine, like diamond, so cut gems with a good polish are very bright, and the dispersion is about four times that of diamond. Consequently, faceted gems are alive with fire and color, w...
Sphene View Profile
Sphene is also known as "titanite" due to its titanium content. They are yellow, orange, brown or green gems with many gradations between those colors. The usual colors are created by iron and rare-earth element impurities. Sphene is found primarily in Madagascar, Mexico, Canada and, historically, in Austria. Although reasonably available in the marketplace, it is virtually unknown ...
Spinel View Profile
Spinel is an important gem historically because it has been confused with other gemstones, especially ruby. Large red gems such as the Black Princes Ruby and the Timur Ruby in the Crown Jewels of England have proven to be fine large red spinels (ruby spinel). In ancient times this material was known as Balas ruby.
Spurrite View Profile
This attractive but rather rare mineral has seldom been cut as a gemstone. Polished slabs and rough material appeared in 1986 at a mineral show in substantial quantities, however. This material is Mexican, translucent to opaque, and medium to dark purple in color.
Staurolite View Profile
Faceted staurolites are extremely rare and always small and dark in color. Staurolite forms very interesting crystals, but cut gems are too dark to be attractive and lack fire. Nonetheless they are true rarities and prized for their scarcity. Zincian staurolite, though very rare, is lighter in color and more attractive as a cut gem; S.G. 3.79, indices 1.721—1.731; trichroic: gree...
Stibiotantalite View Profile
Cut stibiotantalite strongly resembles sphalerite, but the luster is much less brilliant (sphalerite can be adamantine), and stibiotantalite is usually more heavily included, as well as strongly birefringent. This birefringence gives the cut gems a sleepy look due to doubling of back facets as seen through the table. Cut gems over 2-3 carats are among the rarest of collector items.
Stichtite View Profile
Stichtite is not facetable, but the pink color is quite striking in cabochons. Cut stones are especially beautiful when there are other minerals present to add splashes of green and yellow. This material somewhat resembles a pink, granular material from the USSR referred to as canasite.
Stolzite View Profile
Stolzite is a rare mineral; much rarer than wulfenite and usually occurs in very minute crystals. However, the Australian crystals may be up to 1 inch...
Strontianite View Profile
Strontianite is a collector’s oddity, with no spectacular properties to recommend it. Colors are usually pale and there is little fire; in addition, the high birefringence doubles hack facets and kills the brilliance of the stone. Cut strontianites are, however, decidedly uncommon and worth pursuing for their scarcity value.
Sugilite View Profile
Grape Jelly Purple, is how the color of this gem is described. In spite of the popularity of that food in the US, the gem isn't very popular among consumers. Even sophisticated gem shoppers ignore this beautiful gem. Most sugilite sales are in Asia, very few in North America.
Sulfur View Profile
Sulfur has no use as a gem. It is so heat sensitive that a crystal held in the hand may crack due to thermal shock. A crystal dropped from a height of several inches would most likely chip or crack—not ideal properties for jewelry stones! Cutting sulfur is enormously difficult, but the challenge has been met by cutters who have succeeded in fashioning stones of small size. Facetab...
Taafeite View Profile
Taaffeite reacts to most gemological tests like mauve-colored spinel, but can be distinguished on the basis of its birefringence. Additional stones will undoubtedly be discovered in the future (generally misidentified as spinel) as collectors search for these rarities. Taaffeite is one of the rarest of mineral species, and surely among the very rarest and most desirable of all colle...
Talc View Profile
An overview on Talc Jewelry and Gemstones. Covers details and essential information on the physical properties and characteristics of Talc gemstones.
Tantalite View Profile
Tantalite is too dark to be of use as a faceted gem but is sometimes cut as a collector curiosity, either faceted or in cabochons. These could be of any desired size.
Tanzanite View Profile
Truly a modern gemstone, transparent zoisite of a naturally reddish brown color which can be heated to a stable blue to violet, was discovered in the shadow of Mt. Kilamanjaro in 1969. Although other varieties of opaque zoisite were well known, they made no impact on the gem market. Tanzanite's rise to prominence among retail jewelers and the general public has been rapid and dramat...
Tektite View Profile
Tektites were first discovered in 1787 in Czechoslovakia (then Moravia) near the River Moldau, hence the name moldavite. It has been argued that tektites originated as a result of violent explosive activity on the Moon and were thrown all the way to the Earth's surface. Other scientists, currently in the majority, argue that tektites are of terrestrial origin. The issue is being d...
Tephroite View Profile
Tephroite is generally reddish brown and barely translucent. However, it takes a good polish and is massive enough to make good cabochons. Only the New Jersey and Australian localities seem to have provided such material, however. Faceted gems are unknown.
Thomsonite View Profile
Thomsonite cabochons take a high polish but are somewhat brittle. These are especially lovely when a pinkish gray eyelike pattern is present, but such material is rare, Lintonite, from Michigan, is translucent and green and is sometimes mistaken for jade. A faceted thomsonite must be considered a great rarity.
Tiger's Eye View Profile
Crocidolite, (blue asbestos,) alters to quartz, but while retaining its fibrous structure. This material is frequently stained by iron, giving it a golden brown color. We know this material as tigers eye. Unstained pieces, retaining their original blue color, are called Hawks Eye. There are also pieces with both colors.
Topaz View Profile
Topaz of any type is a good jewelry stone and it is historically one of the most important gemstones. With its relatively high refractive index and hardness of 8, with no special sensitivity to chemicals it can be used, with appropriate care, in any jewelry application. Although perfect cleavage does present a caution, this is mostly solved in the cutting stage --cutters generally o...
Tremolite View Profile
It is possible to misidentify tremolite, mistaking it for other amphiboles. Hexagonite is the rarest of the gem varieties of tremolite. If tremolite occurs in very tiny fibrous crystals, densely matted and interlocked, it is then known as nephrite (jade). Material containing more or less parallel fibers is somewhat chatoyant and yields weak catseyes. These are sometimes called ca...
Triphylite (Tryphylite) View Profile
Triphylite is one of the world's rarest gems. The IGS had the extraordinary privilege of examining a discovery of facetable material from Brazil that showed previously unknown characteristics.
Tsavorite Garnet View Profile
Tsavorite is a green colored variety of grossular which is a variety of garnet.
Tugtupite View Profile
Gem collectors prize tugtupite for its rich colors and intense reaction to ultraviolet light. Sporadically used in jewelry, clean, faceted tugtupites are great rarities.
Ulexite View Profile
The fibrous material cuts interesting catseye cabochon gems, but they are curios only since they are much too soft and fragile for wear. The eye can be very strong, however. Sometimes ulexite occurs in seams, consisting of tightly packed parallel fibers. These are transparent along their length, and the packed aggregates act like an array of parallel glass fibers, displaying the pro...
Uvarovite Garnet View Profile
Uvarovite is the rarest of the garnet family. Colored by chromium, it is always a dark, rich green. The crystals are small and most people have only seen examples of druzy on matrix.
Vanadinite View Profile
A faceted vanadinite may be considered a tremendous rarity. Fewer than ten such gems may have been cut. This is unfortunate since the color is rich and beautiful. Arizona crystals tend to be very small, but the ones from Morocco reach a size of several inches.
Variscite View Profile
Variscite has occasionally been used as a turquoise imitation. It is very popular among hobbyists as a cabochon material because of the interesting patterns in the Utah material. Variscite mixed with quartz from Ely, Nevada, has been named Amatrix (for American matrix).
Väyrynenite View Profile
The only reported gems are of Pakistani material, reddish-pink in color, and tiny.
Villiaumite View Profile
Villiaumite is seldom discussed among collectors of rare gemstones because until recently no facetable material was known. The material from Los was reported in 1976 and has been cut into tiny gemstones of deep red color. Despite their small size, they are desirable because so few stones exist. The material from Quebec is larger but very scarce. Villiaumite is somewhat water-soluble...
Vivianite View Profile
Vivianite is so fragile and soft, any faceted gems would be difficult to handle safely, let alone wear. Nevertheless, its blue and green colors are so rich, a few stones (very few) have been cut.
Wardite View Profile
Wardite is another of the many phosphates that have been cut by collectors. It is pale colored and not terribly attractive and is fairly soft and fragile. It is seen far more frequently as cabochons than as faceted stones.
Wavellite View Profile
Wavellite is a very attractive mineral, well-known to collectors. Its radial aggregate crystal clusters can be cut into extremely interesting stones.
Weloganite View Profile
An overview on Weloganite Jewelry and Gemstones. Covers details and essential information on the physical properties and characteristics of Weloganite gems.
Whewellite View Profile
Whewellite is one of the most unusual minerals because of its chemical composition and occurrence. It is seldom seen by collectors, and even less thought of as a faceted gemstone. It is really just a curiosity, and there is nothing intriguing about it except its rarity. The dispersion is fairly high but hard to appreciate because of the usual small size of cut gems.
Wilkeite View Profile
An overview on Wilkeite Jewelry and Gemstones. Covers details and essential information on the physical properties and characteristics of Wilkeite gems.
Willemite View Profile
An overview on Willemite Jewelry and Gemstones. Covers details and essential information on the physical properties and characteristics of Willemite gems.
Witherite View Profile
Witherite is very rarely faceted; if it is faceted, it is quite rare. Stones are not especially beautiful, and they are soft and fragile as well. Their only major attribute is rarity. Witherite is fairly easy to cut but somewhat difficult to polish.
Wollastonite View Profile
Interesting cabochons have been cut from wollastonite, especially from the fibrous material (which yields catseye stones) and the reddish material from Lake Superior’s lsle Royale. Wollastonite is strictly a curiosity and as a mineral is not especially rare. It resembles other white fibrous minerals, however, and is sometimes difficult to identify without using X—ray techniques....
Wulfenite View Profile
Although aesthetically magnificent wulfenite crystals are often too thin, soft, and sensitive to cut for jewelry, rare faceted pieces are greatly prized by collectors. The red of wulfenite, especially from the Red Cloud Mine in Arizona, is one of the richest colors in nature.
Xonotlite View Profile
Xonotlite is strong and can take a good polish. However, these gems are extremely rare, both as a species and cut specimens.
Yugawaralite View Profile
An overview on Yugawaralite Jewelry and Gemstones. Covers details and essential information on the physical properties and characteristics of Yugawaralite.
Zektzerite View Profile
An overview on Zektzerite Jewelry and Gemstones. Covers details and essential information on the physical properties and characteristics of Zektzerite.
Zincite View Profile
Zincite is a very rare mineral, essentially restricted to one important locality. Well, terminated crystals were found only up to about 3-4 inches, but larger masses, weighing several pounds, have been encountered in the ore bodies. These are not especially interesting, but cabochons with red zincite, green willemite, and white calcite, peppered with black franklinite, are unique to...
Zircon View Profile
Zircon is an underrated but magnificent gemstone. When it is properly cut, it rivals diamond in beauty, but often the cutting is not correct and the gem is relatively dull and lifeless. The dispersion is very high, close to that of diamond. Zircon is very brittle and edges of stones are easily chipped and abraded. Zircon must be worn carefully to prevent damage. The range of color i...