Gemstone Treatment Codes
The AGTA has proposed the use of gemstone treatment codes to promote disclosure and a common language for these procedures. Learn what these codes…
The AGTA has proposed the use of gemstone treatment codes to promote disclosure and a common language for these procedures. Learn what these codes…
Clinohumites and chondrodites can make beautiful gemstones with rich colors, but these members of the humite mineral group are rare and little…
Fibrous pectolite has long been a curiosity for gem collectors. Compact material can make wonderful cabochons, and transparent crystals are…
To date, only one locality — Mont St. Hilaire, Quebec, Canada — has produced facetable serandite. These extremely rare gems are very small…
Väyrynenite is a very rare mineral. Crystals as well as faceted gemstones in reddish, pinkish, and orange colors are prized collector’s items.…
Deep red pyrargyrite occurs in a number of localities in well-formed but small crystals. However, facetable rough is rare and difficult to cut,…
Although lapidaries can cut cabochons and decorative objects from massive or translucent eudialyte crystals, transparent material suitable…
Dioptase has a beautiful, emerald-like green color. Although this mineral isn’t rare, gems are seldom faceted because of a paucity of clean…
As beautiful as a diamond, a faceted cerussite actually has higher dispersion and usually excellent transparency, colorless or light body color,…
Vivianite is so fragile and soft, any faceted gems would be difficult to handle safely, let alone wear. Nevertheless, its blue and green colors…
Ranging in color from pale yellow to brown, reddish, and green, microlite cabochons are prized by collectors. Faceted gems are very beautiful…
Very rare milarite crystals can occur in green and yellow colors. Transparent material can yield small but pleasant looking faceted gems for collectors.…
One of the major mineral constituents of lapis lazuli, haüyne is rarely found and faceted as a distinct gemstone. Collectors prize its beautiful,…
Although not suitable for jewelry, apophyllite is a popular collector’s piece. Perhaps the whitest of all gems, cut, colorless specimens are…
A relative newcomer to the world of gemstones, ekanite is rare and usually quite radioactive. When cabbed, some ekanites can display a star stone…
Difficult to facet and typically colorless, beryllonite is a rare collector’s gem. Some specimens can show a striking cat’s eye.
Friedelite is not abundant, and gem-quality material is rarely seen even in large collections. Faceted gems are true collector’s items.
One of the rarest of all facetable gems, cut cuprites can show magnificent deep red color. However, these beautiful stones are too fragile for jewelry…
Crystallography is the study of crystalline solids. Learn the most common terms gemologists use to describe the structure of crystal gems.
Collectors prize deep blue azurite crystals, but faceted gems are extremely rare. However, azurite frequently occurs mixed with green malachite,…
Accurately measuring optical properties is critical for identifying gemstones. This article covers the basic terminology and concepts of gemstone…
Seldom seen even in mineral collections, whewellite is very rarely faceted. It’s mostly desired as a curiosity because of its scarcity, chemical…
Gemstone cleavage is a break in a crystal along internal planes. Learn the science behind this and the difference between cleavage, fracture,…
Jeremejevite would make a durable and attractive jewelry stone, but this rare mineral occurs even more rarely as facetable material. Recently,…
Andradite is one of the most sought after garnet species. Although more sources have been discovered in recent decades, gem-quality andradites…
Although hard enough to be worn safely in jewelry, euclase in beautiful colors is rare over a few carats. It’s also a difficult gem to facet.
With striking sky blue to blue-green colors, turquoise has been prized by cultures all over the world for over 5,000 years. Today, the traditional…
Don’t be confused by the name. Zircon is a natural, magnificent, and underrated gemstone that has been worn and treasured since ancient times.…
What is the color of sugilite? Grape jelly purple is a good description. More popular among consumers in Asia than North America, this is a very rare…
A popular variety of colored quartz, rose quartz makes a durable jewelry stone. Although commonly cabbed and carved, more transparent material…
Rubellites are tourmalines with reasonably saturated dark pink to red colors and medium to dark tones. They make excellent jewelry stones, and…
Gypsum is one of the most abundant minerals, but gem-quality crystals are very rare. This material is extremely difficult to facet but very easy…
Bright, silvery metallic cabochons of algodonite and domeykite are attractive and unusual. Faceted pieces are rarely seen but very beautiful…
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.…
Originally known as bixbite, red beryl is one of the rarest, most desirable, and most expensive gemstones. Most fine crystal specimens are zealously…
With light blue and green colors, no cleavage, and high hardness, boracite is an uncommon mineral. Unfortunately for jewelry lovers, faceted…
Large, faceted scheelites are among the most beautiful of all collector’s gemstones. They occur in many colors and fluoresce very brightly.…
Willemite is prized for its intense green fluorescence. Too fragile for jewelry use, faceted specimens are extremely rare.
Although abundant in various lava rocks, leucite is extremely rare in gem-quality form and often has a milky or cloudy look. Faceted stones as well…
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…
Proustite crystals have magnificent red colors and good brilliance. Although facetable, they’re too soft for jewelry use but highly desired…
Xonotlite is strong and can take a good polish. However, these gems are extremely rare, both as a species and cut specimens.
Small, cuttable crystals of very rare zektzerite are found only in a mountainous location in Washington state. Faceted pieces would make prized…
Although aesthetically magnificent wulfenite crystals are often too thin, soft, and sensitive to cut for jewelry, rare faceted pieces are greatly…
Yugawaralite is a very rare colorless to pinkish zeolite mineral. Little facetable material exists, so a cut yugawaralite would be a prized addition…
Pyroxmangite grains are rare, seldom clean enough to facet, and difficult to cut. However, when cut, they are extremely beautiful and rich in color.…
Massive white barite (also called known as baryte) looks like marble and could be used for decorative purposes. In spite of the abundance of good…
Renowned for its delicate blue-green shades, phosphophyllite’s beauty is enhanced by expert cutting. Unfortunately, this gem is quite fragile…
Gemstone luminescence is a glow that occurs when certain stones are subjected to energy such as UV light. This effect can help gemologists identify…
For a long time, rare thaumasite crystals — pale, fragile, and with little to no fire — were interesting primarily as mineral specimens. With…
Pearls are the only gems found within living creatures, both salt and freshwater mollusks. However, most pearls on the market today are cultivated,…
Soft and brittle, rare augelites are difficult to cut and unsuitable for wear. Faceted transparent pieces are only found in very complete gem and…
One of two distinct minerals commonly known as jade, jadeite is the rarer and harder variety. Rich emerald-green jadeite, known as “imperial…
Cassiterite is a durable gemstone with tremendous dispersive fire, especially visible in properly cut pale-colored stones. As the principal…
A little-known gem material of truly exquisite color, sky-blue ceruleite takes a very high polish easily and quickly. However, fine, solid, cuttable…
Though perhaps best known as inclusions within other gems, rutile crystals themselves can be faceted or cabbed as curiosities for collectors.…
Sarcolite is an extremely rare mineral. Tiny, colorless to “fleshy pink” gems have been cut only from material from one locality: Mount Vesuvius.…
Although sulfur is very abundant, facetable material is not. Sulfur is also enormously difficult to cut and almost impossible to wear, so faceted…
With beautiful green to blue-green colors and interesting patterns, variscite is a popular hobbyist material for cabochons.
Although many gems show a cat’s eye effect, when the term “cat’s eye” is used alone, it always refers to the rare gemstone chrysoberyl.…
Massive hemimorphite can have a very delicate, blue color. However, it’s seldom cut because not very much has appeared on the market.
A very durable gemstone, danburite is an excellent choice for jewelry use. Although the mineral isn’t rare, large facetable pieces are scarce.…
Although covellite has attractive blue colors and shows iridescence, this rare mineral is difficult to cut. You can scratch it with a fingernail!…
“Emerald by day, ruby by night,” alexandrite is well known for displaying one of the most remarkable color changes in the gem world — green…
Colemanite is an abundant mineral, and transparent material isn’t rare. However, gem cutters rarely facet these typically pale stones. Difficult…
Until 2001, only three painite crystals were known to exist. Since then, additional discoveries have produced many more specimens of this deep…
Cerulean blue papagoite crystals are too small for faceting. However, massive material mixed with quartz can be cabbed, while quartz crystals…
Brucites are extremely difficult to cut. Although too soft for jewelry use, faceted pieces would be great additions to collections of rare gemstones.…
Brookite usually occurs in very dark colors, transparent only in small fragments. Cuttable crystals are exceedingly rare, making attractive…
Triphylite is one of the world’s rarest gems. The IGS had the extraordinary privilege of examining a discovery of facetable material from Brazil…
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,…
Sapphirines are durable but very rare gemstones. Although named after their typically sapphire-blue color, these gems can occur in different…
When faceted, the members of the axinite mineral group are usually intensely trichroic, with considerable brilliance and rich brown and purple…
Easy to cut but too soft and fragile for jewelry, a faceted witherite would make an unusual addition to a gem collection.
Strongly pleochroic, andalusite can show shades of green, brown, and red when viewed from different directions. Although tough enough for most…
A rather rare mineral, lovely blue-green grandidierite is seldom seen in gem or jewelry collections. Translucent material is sometimes cut into…
Smithsonite occurs across the globe, but facetable crystals are extremely rare. These gems can show a wide range range of rich colors but are too…
Named after the color of sea water, aquamarine is the blue to blue-green member of the beryl family. Readily available and moderately priced, the…
Rare stibiotantalite possesses an interesting mix of physical and optical properties that help distinguish it from other earth-toned gemstones.…
Also known as heliotrope, bloodstone is the traditional March birthstone. This dark green, opaque chalcedony with red to orange spots is a variety…
Gemstone inclusions are materials trapped inside gems as they form. Learn how gemologists use inclusions to help identify gemstones and their…
Rare and difficult to cut, anhydrite is seldom faceted. However, this material can be carved into beautiful objects. “Angelite,” a blue-gray…
Rare phosgenite typically shows pale colors. This material is difficult to cut and too soft for jewelry wear. However, its strong yellowish fluorescence…
Also known as the “cinnamon stone,” hessonite is the yellow-orange to reddish orange variety of grossular garnet. Hessonites can make beautiful,…
Grossular garnets come in almost every color, even colorless, except blue. However, unlike other garnets, they’re rarely red or dark. Often…
Always a dark, rich green color, uvarovite is one of the rarest members of the garnet family. Usually only seen as druzy on matrix, these crystals…
With lovely colors and intense pleochroism, faceted scorodite is a prize for collectors of the rare and unusual. However, it’s too soft for jewelry…
Too soft for jewelry use, legrandite is a popular collector’s mineral because of its intense yellow color and aesthetic crystal groupings.…
Staurolite crystals in opaque cross shapes are popular gemstones. However, this material is very rarely transparent or facetable. These dark…
Anatase occurs in many beautiful colors, such as deep indigo and amber yellow. However, these rare gems are seldom transparent and are usually…
Gem collectors prize tugtupite for its rich colors and intense reaction to ultraviolet light. Sporadically used in jewelry, clean, faceted tugtupites…
Faceted eosphorites in pale colors are quite attractive and easy to cut. However, these very rare gems are too soft for most jewelry use.
Niccolite’s delicate peachy red color and metallic luster looks beautiful when polished. Gem cutters typically carve this gem material into…
Chambersite is an exceedingly rare mineral. Although it has properties suitable for jewelry use, its crystals occur in very small sizes. Few cut…
Although anglesites with pale colors can show great dispersion and brightness, they’re difficult to cut and inadvisable to wear. Faceted pieces…
Although transparent dolomite crystals are fairly abundant and popular collector’s items, faceted gems are soft, fragile, and rarely seen…
Mellite is a rare and unusual organic gemstone. Although soft and fragile, the “honey stone” is quite beautiful when cut.
Datolite is a popular collector’s mineral. Polished sliced nodules can show off very attractive colors. Too soft for regular jewelry use, faceted…
Sphene, also known as titanite, has rich body colors, strong trichroism, and a fire that exceeds diamond. Although softer than many more popular…
Although too brittle for most jewelry use, properly cut apatite gems are truly magnificent. A collector could assemble a suite of as many as twenty…
Although too fragile for most jewelry use, fluorites are often faceted for collectors. They occur in a wide range of attractive colors and can be…
Although not well known, scapolite would make an attractive gem material for both jewelry enthusiasts and mineral collectors. It comes in a wide…
Tanzanite has had a rapid rise to prominence among jewelers and gem enthusiasts. Although naturally reddish brown, this transparent zoisite…
The epidote mineral supergroup contains many related species of interest to collectors. However, epidote itself is the one most likely to be faceted…
Although adamite occurs in many localities, it’s very rarely cut as a gem. This mineral is much too soft and fragile for jewelry. However, collectors…
Siderite is difficult to cut, but this light brown collector’s gem has yielded faceted pieces of great beauty.
Beautiful rose red to pink rhodochrosite crystals are popular with mineral collectors. Although very soft, opaque material has been fashioned…
Gemological formulas identify the chemical composition of gems and minerals. Learn what the symbols, numbers, and parentheses mean.
Probably fewer than a dozen creedite gems have ever been faceted. This rare mineral is rarer still as a cuttable crystal. Too soft to wear, this strictly…
The modern August birthstone, peridot has been prized as a jewelry stone since ancient times. Always green in color but with considerable variations,…
Hurlbutite is an extremely rare mineral. Minute, colorless faceted stones have been cut from fragments.
Sphalerite occurs in many colors. With a dispersion over three times that of diamond and an adamantine luster, faceted specimens make beautiful…
Millerite has a rich, attractive yellow color. Massive millerites can sometimes be cut into cabochons but are too soft for jewelry use. However,…
Adamantine. Silky. Greasy? Gemologists use these and other evocative terms to describe gemstone luster. This simply means how a gem’s surface…
Wavellite is a very attractive mineral, well-known to collectors. Its radial aggregate crystal clusters can be cut into extremely interesting…
Amblygonite gems are usually pale straw yellow. Although they are too soft and cleavable to make good ring stones, collectors prize them if they…
Non-destructive tests are critical for gemologists trying to identify gems. Learn how measuring thermal properties, especially thermal inertia,…
Rhodizite is tough enough to make an excellent jewelry stone. However, it’s quite a rare mineral. Faceted specimens are extremely rare and usually…
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.…
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…
Although this common arsenic sulfide mineral occurs worldwide, cut gem-quality realgar is extremely rare. This fine, red stone is very fragile,…
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,…
Rare phenakite is a very hard gem material suitable for jewelry. Usually colorless, cut stones have little fire but can be very bright.
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.
Colorless pollucites lack fire when cut and are usually small. However, this very rare cesium mineral is a coveted collector’s gem.
Although marketed as “angel skin opal,” “rock wood,” and “mountain leather,” palygorskite is neither opal, wood, nor leather.…
Hureaulite can show rich and lively pink, rose, and orange colors. However, this collector’s gem is rarely cut.
Although faceting chabazite isn’t too difficult, it’s too soft for jewelry. However, only a handful of cut chabazites may exist because facetable…
Tough, easy to cut or carve, and rich in color, typically blue, sodalite is highly desired by hobbyists. Even stones that lack transparency make…
Although hard enough for jewelry use, rare hambergite is a gem for collectors of the unusual. Its combination of high birefringence and very low…
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,…
Gemologists sometimes measure gemstone density or specific gravity to help with gem identification. Learn the basics of this property and how…
Lazulite makes a magnificent, deep blue gemstone. Although the mineral itself occurs widely, gem-quality rough is limited. Specimens are prized…
Historically a popular black gem, jet has declined in popularity in modern times. Although jet jewelry has been long associated with mourning,…
With dispersion higher than diamond and sapphire blue body color, benitoite is one of the most attractive of all rare gems. Gem-quality crystals…
Gem-quality, colorless, facetable petalite is rare and desirable to collectors. More so if the stones are large and free of inclusions.
Marcasite has a long history of use as a decorative and jewelry material. However, this brassy colored, metallic stone is quite brittle and seldom…
Magnificent red cinnabar is extremely soft and fragile, so faceted material is rare. It’s cut primarily for collectors and carvings.
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,…
Pure blue chrysocolla is extremely soft but interesting to gem collectors. On the other hand, chrysocolla that forms as gel mixed with silica and…
Hematite has a long history of use as a pigment. As a gemstone, this material is often carved but very rarely faceted. Despite its association with…
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…
Chrysoprase is apple-green chalcedony that derives its color from nickel. Its hardness and striking color make it a popular gemstone for jewelry…
Gems of completely transparent magnesite are both rare and beautiful. The huge birefringence is obvious even in small stones, and larger gems…
Like their marine cousins, many freshwater mollusks can produce pearls. However, this rarely occurs in nature. Today, the majority of pearls…
Found all over the world, moonstone is prized for its blue to white adularescence — a billowy, moonlight-like sheen. Despite being somewhat…
Ammolite is a rare, iridescent, gem-quality material cut from the fossilized shells of extinct sea creatures. Found only in the Bearpaw Formation…
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…
Malaia or malaya garnets are typically light to dark, slightly pinkish orange, reddish orange, or yellowish orange in color. This a popular…
One of the rarer varieties in the garnet group, Mali garnet is a blend of grossular and andradite. This gemstone has great brilliance and a high dispersion.…
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…
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,…
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…
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…
Malachite is one of the most popular and beautiful of decorative stones. lts rich, patterned coloration in shades of green is unique among gems.…
Technically, chalcedony (kal SED’ uh nee) is any form of microcrystalline or cryptocrystalline quartz, (meaning any form of quartz whose crystals…
Agate is a variety of chalcedony that exists in many colors and is often commercially dyed. Agate is distinguished by having multiple colors.…
Obsidian is an attractive material and displays a wide variety of appearances. Snowflake obsidian, with spherulites of cristobalite, is widely…
The traditional November birthstone, topaz is a popular gem. Although frequently associated with golden yellow as well as blue, it can be found…
Few gems have held our attention over millennia as well as sapphire. The pure blue colors and excellent durability of this gem-quality member of…
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…
Identifying gemstone treatments is difficult even for experienced gemologists. Learn about the many different ways gem color and clarity are…
Learn about the different crystal growth methods used to artificially create gemstones in laboratories.
Learn about synthetic diamond creation and the challenges buyers face determining whether a diamond is natural or artificial.
Many varieties of gems besides diamond can be created in the laboratory. Our synthetic gemstone guide covers many examples and explains their…
Anorthite is the most calcic of the plagioclases, and sometimes makes up a distinctive rock known as anorthosite, which has been extensively studied.…
Bytownite is found in basic plutonic rocks, some metamorphic rocks, and meteorites.
These feldspars are rarely encountered in gem form. Andesine’s occurrence is widespread throughout the world, in a great variety of rock types…
Oligoclase gems are feldspars that are part of a solid state series between albite and anothrite.
Albite, usually colorless but sometimes yellow, pink, gray or reddish. Translucent albite is sometime colored green by chrome jadeite. It is…
Peristerite is primarily oligoclase with a complex mixture of feldspars. It has iridescence that is either blue or white.
Perthite is a blend of microcline, albite and oligoclase. It is usually brown and white. May have gold or white iridescence.
Sanidine is a mineral of volcanic rocks, rarely considered a gem. While occasionally brown or yellow, most examples are colorless.
Orthoclase is best known for moonstone. It is occasionally a transparent, faceted gem. Note that moonstone is occasionally a labradorite.
Amazonite is a variety of microcline, which is itself a variety of feldspar.
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…
Rhodolites are purplish red garnets, a blend between almandine and pyrope in composition. These durable gems have become popular jewelry stones.…
An overview on Zunyite Jewelry and Gemstones. Covers details and essential information on the physical properties and characteristics of Zunyite…
Zincite is a very rare mineral, essentially restricted to one important locality. Well, terminated crystals were found only up to about 3-4 inches,…
An overview on Wilkeite Jewelry and Gemstones. Covers details and essential information on the physical properties and characteristics of Wilkeite…
An overview on Weloganite Jewelry and Gemstones. Covers details and essential information on the physical properties and characteristics of…
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…
Interesting cabochons have been cut from wollastonite, especially from the fibrous material (which yields catseye stones) and the reddish material…
Villiaumite is seldom discussed among collectors of rare gemstones because until recently no facetable material was known. The material from…
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…
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…
It is possible to misidentify tremolite, mistaking it for other amphiboles. Hexagonite is the rarest of the gem varieties of tremolite. If tremolite…
Taaffeite reacts to most gemological tests like mauve-colored spinel, but can be distinguished on the basis of its birefringence. Additional…
An overview on Talc Jewelry and Gemstones. Covers details and essential information on the physical properties and characteristics of Talc gemstones.…
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…
Strontianite is a collector’s oddity, with no spectacular properties to recommend it. Colors are usually pale and there is little fire; in addition,…
Tektites were first discovered in 1787 in Czechoslovakia (then Moravia) near the River Moldau, hence the name moldavite. It has been argued…
Tephroite is generally reddish brown and barely translucent. However, it takes a good polish and is massive enough to make good cabochons. Only…
Thomsonite cabochons take a high polish but are somewhat brittle. These are especially lovely when a pinkish gray eyelike pattern is present,…
Stichtite is not facetable, but the pink color is quite striking in cabochons. Cut stones are especially beautiful when there are other minerals…
Stolzite is a rare mineral; much rarer than wulfenite and usually occurs in very minute crystals. However, the Australian crystals may be up to…
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…
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…
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…
Simpsonite is an extremely rare gemstone. The material from Western Australia is bright yellow-orange and very beautiful. The mineral is hard…
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,…
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…
Shortite is an exceedingly rare, not overly attractive mineral. Cut gems are among the rarest of all faceted stones. The material is a carbonate…
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,…
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. …
An overview on Sellaite Jewelry and Gemstones. Covers details and essential information on the physical properties and characteristics of Sellaite…
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…
Samarskite is a very heavy material from which lustrous black to brownish cabochons are sometimes cut as curiosities. The material is rather brittle…
Pyrophyllite resembles talc in many ways and is indistinguishable by eye from soapstone. Chemical tests are needed to distinguish them. North…
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…
An overview on Pyrrhotite Jewelry and Gemstones. Covers details and essential information on the physical properties and characteristics of…
The gem variety of pumpellyite, chlorastrolite, is best known from the Lake Superior district of the United States. It typically forms aggregates…
An overview on Prosopite Jewelry and Gemstones. Covers details and essential information on the physical properties and characteristics of…
An overview on Powellite Jewelry and Gems. Covers details and essential information on the physical properties and characteristics of Powellite…
Prehnite is popular as a cabochon material among hobbyists because of its lovely green and blue-green to yellow colors. Completely transparent…
This material is never transparent and is too soft for wear. However, cabochons are a magnificent purplish rose hues that have essentially no counterpart…
An overview on Parisite Jewelry and Gemstones. Covers details and essential information on the physical properties and characteristics of Parisite…
Pentlandite resembles other yellowish metallic minerals and is cut by collectors as a curiosity. The cut stones are quite attractive but too soft…
The amphibole group is very large and extremely complex and contains numerous distinct species that vary subtly in chemistry and physical properties.…
Periclase has been synthesized in large masses in the laboratory, but these have no market significance. A faceted natural periclase would be…
An overview on Neptunite Jewelry and Gemstones. Covers details and essential information on the physical properties and characteristics of…
All three minerals are fibrous or elongated zeolite minerals. Faceted gems are almost always elongated emerald cuts or step-cuts.
A variety called elaeolite is red, green, brown, or gray, massive or in crystals filled with minute inclusions. These inclusions produce…
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…
Kurnakovite is similar to inderite. Both are colorless and very uninteresting as faceted gems, which is why very few have been cut. The material…
Monazite may be partially metamict, with N=1.79. Stones can be an attractive yellow or brown color but are usually small.
Transparent mimetite crystals are extremely rare, and very few have ever been faceted. Cabochons with rich orange and yellow colors have been…
Compact, fibrous material is cabbed because the fibers provide a chatoyancy that sometimes yields weak catseyes. Coloration in the material…
Meliphanite is an extremely rare gemstone, and perhaps fewer than 5-10 faceted stones have ever been cut.
Manganotantalite makes a spectacular red brown gem that is a very rare collector’s item. Transparent material is light enough in color to allow…
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.…
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…
Reddish granular or massive lepidolite is usually slabbed for ornamental purposes, such as ashtrays paperweights, and bookends. Faceted micas…
Lawsonite is extremely rare as a faceted stone, seldom reported and generally unavailable.
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…
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…
Star kornerupine also has been found (Mogok, Myanmar) but is very rare. Kornerupine is generally dark brown or green and not very attractive…
Kämmererite is a beautiful but rare mineral. It is micaceous; consequently, it is extraordinarily difficult to facet, which has severely limited…
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…
It should not be difficult to find numerous small faceted huebnerites among larger gemstone collections. Certainly ample material exists to…
Howlite is always opaque in nodules; it is an abundant material and easy to acquire. Sometimes it contains black, threadlike impurities resembling…
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…
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…
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…
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…
This mineral is not abundant and is known from various localities. Cabochons are cut merely as curiosities, as they have no special features that…
Euxenite is seldom seen in collections. Most collectors would not regard the mineral as facetable, but transparent fragments and areas of crystals…
Ettringite is not generally facetable; any cut stone would be considered an extreme rarity. South African material has yielded minute stones,…
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…
Dumortierite is a beautiful and very hard material, eminently suitable for jewelry. The cabochon material is the only generally known form, since…
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…
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,…
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,…
Cut cryolite is somewhat translucent, and has a “sleepy” look. The cuttable material has a very low birefringence, is colorless, and very soft—not…
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…
The material usually seen on the market as “canasite” is purplish in color. It is frequently confused with another purplish material, a member…
Calcite is common and abundant throughout the world. The material has little intrinsic value since it is not scarce. However, calcite is one of…
Bustamite is very similar in appearance and properties to rhodonite. The Japanese crystals are very rich in Mn. The color, when fresh, is paler…
Breithauptite is a curiosity cut for collectors, although it could be worn with care in jewelry. The color is extremely lovely, a delicate reddish…
The crystal structure of cordierite has many similarities to that of beryl; indialite, the dimorph, in fact has the same structure as beryl. Iolite…
Cabochons are interesting because of the lovely reddish metallic appearance of this mineral. Cut stones are infrequently seen and are cut only…
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…
Chromite is shiny and black, and makes a curious-looking cabochon with no special attraction. Occasionally, a cabochon has a reddish color. The…
Cut childrenite is a great rarity, and all gems are small. Cut eosphorite is more abundantly available, though both materials are very scarce.…
The only reported cut catapleiite is from Mte. Ste. Hilaire, Quebec, Canada, in the form of tiny colorless gems.
Bornite is suitable only for cabochons. The bronzy color rapidly tarnishes in air to a magnificent iridescent color display, mostly purple, but…
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…
Extremely rare as a cut gem, even in very complete collections. Many of the minerals in the tantalite group have been faceted; bismutotantalite…
Bayldonite is a nondescript greenish material that has been cut into cabochons by enterprising collectors of the unusual. Cut bayldonites are…
Large colorless crystals of Analcime are a great rarity although small transparent crystals are abundant. Faceted gems are extremely rare and…
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,…
Gemstone color measurements are hard to make with conventional color-order systems. Learn how recent colorimetry tech advances have improved…
The spectroscope is a device that separates white light into an optical spectrum of component colors that can aid in gemstone and mineral identification.…
The color of a mineral or gemstone is one of the primary attributes used for identification,but it is, unfortunately, one of the least diagnostic…
Heliodor is a member of the beryl family. This stone is known for its range of yellow colors — from pale yellow, greenish yellow, orange-yellow,…
Tech advances and market forces make it essential for gem buyers to know the science behind synthetic gemstones and gem formation. Learn the basics…
Tourmaline is one of our most popular gems. No other mineral comes in more colors and some of the combinations are in a class by themselves.
An overview on Labradorite Jewelry and Gemstones. Covers details and essential information on the physical properties and characteristics…
An overview on Quartz Jewelry and Gemstones. Covers details and essential information on the physical properties and characteristics of a Quartz…
Diamond is the most romanticized and heavily marketed of all gemstones. Nearly every jewelry establishment handles diamonds, even if it has no…
Emerald has been synonymous with the color green since ancient times. A fine emerald is a truly breathtaking sight, and this member of the beryl…
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