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…
Articles by
Joel Arem
Humite Value, Price, and Jewelry Information
Clinohumites and chondrodites can make beautiful gemstones with rich colors, but these members of the humite mineral group are rare and little…
Pectolite (Larimar) Value, Price, and Jewelry Information
Fibrous pectolite has long been a curiosity for gem collectors. Compact material can make wonderful cabochons, and transparent crystals are…
Serandite Value, Price, and Jewelry Information
To date, only one locality — Mont St. Hilaire, Quebec, Canada — has produced facetable serandite. These extremely rare gems are very small…
Väyrynenite Value, Price, and Jewelry Information
Väyrynenite is a very rare mineral. Crystals as well as faceted gemstones in reddish, pinkish, and orange colors are prized collector’s items.…
Pyrargyrite Value, Price, and Jewelry Information
Deep red pyrargyrite occurs in a number of localities in well-formed but small crystals. However, facetable rough is rare and difficult to cut,…
Eudialyte Value, Price, and Jewelry Information
Although lapidaries can cut cabochons and decorative objects from massive or translucent eudialyte crystals, transparent material suitable…
Dioptase Value, Price, and Jewelry Information
Dioptase has a beautiful, emerald-like green color. Although this mineral isn’t rare, gems are seldom faceted because of a paucity of clean…
Cerussite Value, Price, and Jewelry Information
As beautiful as a diamond, a faceted cerussite actually has higher dispersion and usually excellent transparency, colorless or light body color,…
Vivianite Value, Price, and Jewelry Information
Vivianite is so fragile and soft, any faceted gems would be difficult to handle safely, let alone wear. Nevertheless, its blue and green colors…
Microlite Value, Price, and Jewelry Information
Ranging in color from pale yellow to brown, reddish, and green, microlite cabochons are prized by collectors. Faceted gems are very beautiful…
Milarite Value, Price, and Jewelry Information
Very rare milarite crystals can occur in green and yellow colors. Transparent material can yield small but pleasant looking faceted gems for collectors.…
Haüyne Value, Price, and Jewelry Information
One of the major mineral constituents of lapis lazuli, haüyne is rarely found and faceted as a distinct gemstone. Collectors prize its beautiful,…
Apophyllite Value, Price, and Jewelry Information
Although not suitable for jewelry, apophyllite is a popular collector’s piece. Perhaps the whitest of all gems, cut, colorless specimens are…
Ekanite Value, Price, and Jewelry Information
A relative newcomer to the world of gemstones, ekanite is rare and usually quite radioactive. When cabbed, some ekanites can display a star stone…
Beryllonite Value, Price, and Jewelry Information
Difficult to facet and typically colorless, beryllonite is a rare collector’s gem. Some specimens can show a striking cat’s eye.
Friedelite Value, Price, and Jewelry Information
Friedelite is not abundant, and gem-quality material is rarely seen even in large collections. Faceted gems are true collector’s items.
Cuprite Value, Price, and Jewelry Information
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…
Descriptive Crystallography for Gemologists
Crystallography is the study of crystalline solids. Learn the most common terms gemologists use to describe the structure of crystal gems.
Azurite Value, Price, and Jewelry Information
Collectors prize deep blue azurite crystals, but faceted gems are extremely rare. However, azurite frequently occurs mixed with green malachite,…
Gemstone Optics: The Basics
Accurately measuring optical properties is critical for identifying gemstones. This article covers the basic terminology and concepts of gemstone…
Whewellite Value, Price, and Jewelry Information
Seldom seen even in mineral collections, whewellite is very rarely faceted. It’s mostly desired as a curiosity because of its scarcity, chemical…
What is Gemstone Cleavage?
Gemstone cleavage is a break in a crystal along internal planes. Learn the science behind this and the difference between cleavage, fracture,…
Jeremejevite Value, Price, and Jewelry Information
Jeremejevite would make a durable and attractive jewelry stone, but this rare mineral occurs even more rarely as facetable material. Recently,…
Andradite Garnet Value, Price, and Jewelry Information
Andradite is one of the most sought after garnet species. Although more sources have been discovered in recent decades, gem-quality andradites…
Euclase Value, Price, and Jewelry Information
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.
Turquoise Value, Price, and Jewelry Information
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…
Zircon Value, Price, and Jewelry Information
Don’t be confused by the name. Zircon is a natural, magnificent, and underrated gemstone that has been worn and treasured since ancient times.…
Sugilite Value, Price, and Jewelry Information
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…
Rose Quartz Value, Price, and Jewelry Information
A popular variety of colored quartz, rose quartz makes a durable jewelry stone. Although commonly cabbed and carved, more transparent material…
Rubellite Tourmaline Value, Price, and Jewelry Information
Rubellites are tourmalines with reasonably saturated dark pink to red colors and medium to dark tones. They make excellent jewelry stones, and…
Gypsum Value, Price, and Jewelry Information
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…
Algodonite Value, Price, and Jewelry Information
Bright, silvery metallic cabochons of algodonite and domeykite are attractive and unusual. Faceted pieces are rarely seen but very beautiful…
Crocoite Value, Price, and Jewelry Information
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.…
Red Beryl Value, Price, and Jewelry Information
Originally known as bixbite, red beryl is one of the rarest, most desirable, and most expensive gemstones. Most fine crystal specimens are zealously…
Boracite Value, Price, and Jewelry Information
With light blue and green colors, no cleavage, and high hardness, boracite is an uncommon mineral. Unfortunately for jewelry lovers, faceted…
Scheelite Value, Price, and Jewelry Information
Large, faceted scheelites are among the most beautiful of all collector’s gemstones. They occur in many colors and fluoresce very brightly.…
Willemite Value, Price, and Jewelry Information
Willemite is prized for its intense green fluorescence. Too fragile for jewelry use, faceted specimens are extremely rare.
Leucite Value, Price, and Jewelry Information
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 Value, Price, and Jewelry Information
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 Value, Price, and Jewelry Information
Proustite crystals have magnificent red colors and good brilliance. Although facetable, they’re too soft for jewelry use but highly desired…
Xonotlite Value, Price, and Jewelry Information
Xonotlite is strong and can take a good polish. However, these gems are extremely rare, both as a species and cut specimens.
Zektzerite Value, Price, and Jewelry Information
Small, cuttable crystals of very rare zektzerite are found only in a mountainous location in Washington state. Faceted pieces would make prized…
Wulfenite Value, Price, and Jewelry Information
Although aesthetically magnificent wulfenite crystals are often too thin, soft, and sensitive to cut for jewelry, rare faceted pieces are greatly…
Yugawaralite Value, Price, and Jewelry Information
Yugawaralite is a very rare colorless to pinkish zeolite mineral. Little facetable material exists, so a cut yugawaralite would be a prized addition…
Pyroxmangite Value, Price, and Jewelry Information
Pyroxmangite grains are rare, seldom clean enough to facet, and difficult to cut. However, when cut, they are extremely beautiful and rich in color.…
Barite Value, Price, and Jewelry Information
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…
Phosphophyllite Value, Price, and Jewelry Information
Renowned for its delicate blue-green shades, phosphophyllite’s beauty is enhanced by expert cutting. Unfortunately, this gem is quite fragile…
What is Gemstone Luminescence?
Gemstone luminescence is a glow that occurs when certain stones are subjected to energy such as UV light. This effect can help gemologists identify…
Thaumasite Value, Price, and Jewelry Information
For a long time, rare thaumasite crystals — pale, fragile, and with little to no fire — were interesting primarily as mineral specimens. With…
Pearl Value, Price, and Jewelry Information
Pearls are the only gems found within living creatures, both salt and freshwater mollusks. However, most pearls on the market today are cultivated,…
Augelite Value, Price, and Jewelry Information
Soft and brittle, rare augelites are difficult to cut and unsuitable for wear. Faceted transparent pieces are only found in very complete gem and…
Jadeite Value, Price, and Jewelry Information
One of two distinct minerals commonly known as jade, jadeite is the rarer and harder variety. Rich emerald-green jadeite, known as “imperial…
Cassiterite Value, Price, and Jewelry Information
Cassiterite is a durable gemstone with tremendous dispersive fire, especially visible in properly cut pale-colored stones. As the principal…
Ceruleite Value, Price, and Jewelry Information
A little-known gem material of truly exquisite color, sky-blue ceruleite takes a very high polish easily and quickly. However, fine, solid, cuttable…
Rutile Value, Price, and Jewelry Information
Though perhaps best known as inclusions within other gems, rutile crystals themselves can be faceted or cabbed as curiosities for collectors.…
Sarcolite Value, Price, and Jewelry Information
Sarcolite is an extremely rare mineral. Tiny, colorless to “fleshy pink” gems have been cut only from material from one locality: Mount Vesuvius.…
Sulfur Value, Price, and Jewelry Information
Although sulfur is very abundant, facetable material is not. Sulfur is also enormously difficult to cut and almost impossible to wear, so faceted…
Variscite Value, Price, and Jewelry Information
With beautiful green to blue-green colors and interesting patterns, variscite is a popular hobbyist material for cabochons.
Chrysoberyl Value, Price, and Jewelry Information
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.…
Hemimorphite Value, Price, and Jewelry Information
Massive hemimorphite can have a very delicate, blue color. However, it’s seldom cut because not very much has appeared on the market.
Danburite Value, Price, and Jewelry Information
A very durable gemstone, danburite is an excellent choice for jewelry use. Although the mineral isn’t rare, large facetable pieces are scarce.…
Covellite Value, Price, and Jewelry Information
Although covellite has attractive blue colors and shows iridescence, this rare mineral is difficult to cut. You can scratch it with a fingernail!…
Alexandrite Value, Price, and Jewelry Information
“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 Value, Price, and Jewelry Information
Colemanite is an abundant mineral, and transparent material isn’t rare. However, gem cutters rarely facet these typically pale stones. Difficult…
Painite Value, Price, and Jewelry Information
Until 2001, only three painite crystals were known to exist. Since then, additional discoveries have produced many more specimens of this deep…
Papagoite Value, Price, and Jewelry Information
Cerulean blue papagoite crystals are too small for faceting. However, massive material mixed with quartz can be cabbed, while quartz crystals…
Brucite Value, Price, and Jewelry Information
Brucites are extremely difficult to cut. Although too soft for jewelry use, faceted pieces would be great additions to collections of rare gemstones.…
Brookite Value, Price, and Jewelry Information
Brookite usually occurs in very dark colors, transparent only in small fragments. Cuttable crystals are exceedingly rare, making attractive…
Triphylite (Tryphylite) Value, Price, and Jewelry Information
Triphylite is one of the world’s rarest gems. The IGS had the extraordinary privilege of examining a discovery of facetable material from Brazil…
Rhodonite Value, Price, and Jewelry Information
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,…
Sapphirine Value, Price, and Jewelry Information
Sapphirines are durable but very rare gemstones. Although named after their typically sapphire-blue color, these gems can occur in different…
Axinite Value, Price, and Jewelry Information
When faceted, the members of the axinite mineral group are usually intensely trichroic, with considerable brilliance and rich brown and purple…
Witherite Value, Price, and Jewelry Information
Easy to cut but too soft and fragile for jewelry, a faceted witherite would make an unusual addition to a gem collection.
Andalusite Value, Price, and Jewelry Information
Strongly pleochroic, andalusite can show shades of green, brown, and red when viewed from different directions. Although tough enough for most…
Grandidierite Value, Price, and Jewelry Information
A rather rare mineral, lovely blue-green grandidierite is seldom seen in gem or jewelry collections. Translucent material is sometimes cut into…
Smithsonite Value, Price, and Jewelry Information
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…
Aquamarine Value, Price, and Jewelry Information
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…
Stibiotantalite Value, Price, and Jewelry Information
Rare stibiotantalite possesses an interesting mix of physical and optical properties that help distinguish it from other earth-toned gemstones.…
Bloodstone Value, Price, and Jewelry Information
Also known as heliotrope, bloodstone is the traditional March birthstone. This dark green, opaque chalcedony with red to orange spots is a variety…
An Introduction to Gemstone Inclusions
Gemstone inclusions are materials trapped inside gems as they form. Learn how gemologists use inclusions to help identify gemstones and their…
Anhydrite (Angelite) Value, Price, and Jewelry Information
Rare and difficult to cut, anhydrite is seldom faceted. However, this material can be carved into beautiful objects. “Angelite,” a blue-gray…
Phosgenite Value, Price, and Jewelry Information
Rare phosgenite typically shows pale colors. This material is difficult to cut and too soft for jewelry wear. However, its strong yellowish fluorescence…
Hessonite Garnet Value, Price, and Jewelry Information
Also known as the “cinnamon stone,” hessonite is the yellow-orange to reddish orange variety of grossular garnet. Hessonites can make beautiful,…
Grossular Garnet Value, Price, and Jewelry Information
Grossular garnets come in almost every color, even colorless, except blue. However, unlike other garnets, they’re rarely red or dark. Often…
Uvarovite Garnet Value, Price, and Jewelry Information
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…
Scorodite Value, Price, and Jewelry Information
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…
Legrandite Value, Price, and Jewelry Information
Too soft for jewelry use, legrandite is a popular collector’s mineral because of its intense yellow color and aesthetic crystal groupings.…
Staurolite Value, Price, and Jewelry Information
Staurolite crystals in opaque cross shapes are popular gemstones. However, this material is very rarely transparent or facetable. These dark…
Anatase Value, Price, and Jewelry Information
Anatase occurs in many beautiful colors, such as deep indigo and amber yellow. However, these rare gems are seldom transparent and are usually…
Tugtupite Value, Price, and Jewelry Information
Gem collectors prize tugtupite for its rich colors and intense reaction to ultraviolet light. Sporadically used in jewelry, clean, faceted tugtupites…
Eosphorite Value, Price, and Jewelry Information
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 (Nickeline) Value, Price, and Jewelry Information
Niccolite’s delicate peachy red color and metallic luster looks beautiful when polished. Gem cutters typically carve this gem material into…
Chambersite Value, Price, and Jewelry Information
Chambersite is an exceedingly rare mineral. Although it has properties suitable for jewelry use, its crystals occur in very small sizes. Few cut…
Anglesite Value, Price, and Jewelry Information
Although anglesites with pale colors can show great dispersion and brightness, they’re difficult to cut and inadvisable to wear. Faceted pieces…
Dolomite Value, Price, and Jewelry Information
Although transparent dolomite crystals are fairly abundant and popular collector’s items, faceted gems are soft, fragile, and rarely seen…
Mellite Value, Price, and Jewelry Information
Mellite is a rare and unusual organic gemstone. Although soft and fragile, the “honey stone” is quite beautiful when cut.
Datolite Value, Price, and Jewelry Information
Datolite is a popular collector’s mineral. Polished sliced nodules can show off very attractive colors. Too soft for regular jewelry use, faceted…
Sphene (Titanite) Value, Price, and Jewelry Information
Sphene, also known as titanite, has rich body colors, strong trichroism, and a fire that exceeds diamond. Although softer than many more popular…
Apatite Value, Price, and Jewelry Information
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…
Fluorite Value, Price, and Jewelry Information
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…
Scapolite Value, Price, and Jewelry Information
Although not well known, scapolite would make an attractive gem material for both jewelry enthusiasts and mineral collectors. It comes in a wide…
Tanzanite (Zoisite) Value, Price, and Jewelry Information
Tanzanite has had a rapid rise to prominence among jewelers and gem enthusiasts. Although naturally reddish brown, this transparent zoisite…
Epidote Value, Price, and Jewelry Information
The epidote mineral supergroup contains many related species of interest to collectors. However, epidote itself is the one most likely to be faceted…
Adamite Value, Price, and Jewelry Information
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 Value, Price, and Jewelry Information
Siderite is difficult to cut, but this light brown collector’s gem has yielded faceted pieces of great beauty.
Rhodochrosite Value, Price, and Jewelry Information
Beautiful rose red to pink rhodochrosite crystals are popular with mineral collectors. Although very soft, opaque material has been fashioned…
Understanding Gemological Formulas
Gemological formulas identify the chemical composition of gems and minerals. Learn what the symbols, numbers, and parentheses mean.
Creedite Value, Price, and Jewelry Information
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…
Peridot Value, Price, and Jewelry Information
The modern August birthstone, peridot has been prized as a jewelry stone since ancient times. Always green in color but with considerable variations,…
Hurlbutite Value, Price, and Jewelry Information
Hurlbutite is an extremely rare mineral. Minute, colorless faceted stones have been cut from fragments.
Sphalerite Value, Price, and Jewelry Information
Sphalerite occurs in many colors. With a dispersion over three times that of diamond and an adamantine luster, faceted specimens make beautiful…
Millerite Value, Price, and Jewelry Information
Millerite has a rich, attractive yellow color. Massive millerites can sometimes be cut into cabochons but are too soft for jewelry use. However,…
What is Gemstone Luster?
Adamantine. Silky. Greasy? Gemologists use these and other evocative terms to describe gemstone luster. This simply means how a gem’s surface…
Wavellite Value, Price, and Jewelry Information
Wavellite is a very attractive mineral, well-known to collectors. Its radial aggregate crystal clusters can be cut into extremely interesting…
Amblygonite Value, Price, and Jewelry Information
Amblygonite gems are usually pale straw yellow. Although they are too soft and cleavable to make good ring stones, collectors prize them if they…
Gemstone Thermal Properties
Non-destructive tests are critical for gemologists trying to identify gems. Learn how measuring thermal properties, especially thermal inertia,…
Rhodizite Value, Price, and Jewelry Information
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 Value, Price, and Jewelry Information
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.…
Realgar Value, Price, and Jewelry Information
Although this common arsenic sulfide mineral occurs worldwide, cut gem-quality realgar is extremely rare. This fine, red stone is very fragile,…
Nephrite Jade Value, Price, and Jewelry Information
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,…
Phenakite Value, Price, and Jewelry Information
Rare phenakite is a very hard gem material suitable for jewelry. Usually colorless, cut stones have little fire but can be very bright.
Chiolite Value, Price, and Jewelry Information
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.
Pollucite Value, Price, and Jewelry Information
Colorless pollucites lack fire when cut and are usually small. However, this very rare cesium mineral is a coveted collector’s gem.
Palygorskite Value, Price, and Jewelry Information
Although marketed as “angel skin opal,” “rock wood,” and “mountain leather,” palygorskite is neither opal, wood, nor leather.…
Hureaulite Value, Price, and Jewelry Information
Hureaulite can show rich and lively pink, rose, and orange colors. However, this collector’s gem is rarely cut.
Chabazite Value, Price, and Jewelry Information
Although faceting chabazite isn’t too difficult, it’s too soft for jewelry. However, only a handful of cut chabazites may exist because facetable…
Sodalite Value, Price, and Jewelry Information
Tough, easy to cut or carve, and rich in color, typically blue, sodalite is highly desired by hobbyists. Even stones that lack transparency make…
Hambergite Value, Price, and Jewelry Information
Although hard enough for jewelry use, rare hambergite is a gem for collectors of the unusual. Its combination of high birefringence and very low…
Celestite Value, Price, and Jewelry Information
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,…
Basics of Gemstone Density and Specific Gravity
Gemologists sometimes measure gemstone density or specific gravity to help with gem identification. Learn the basics of this property and how…
Lazulite Value, Price, and Jewelry Information
Lazulite makes a magnificent, deep blue gemstone. Although the mineral itself occurs widely, gem-quality rough is limited. Specimens are prized…
Jet Value, Price, and Jewelry Information
Historically a popular black gem, jet has declined in popularity in modern times. Although jet jewelry has been long associated with mourning,…
Benitoite Value, Price, and Jewelry Information
With dispersion higher than diamond and sapphire blue body color, benitoite is one of the most attractive of all rare gems. Gem-quality crystals…
Petalite Value, Price, and Jewelry Information
Gem-quality, colorless, facetable petalite is rare and desirable to collectors. More so if the stones are large and free of inclusions.
Marcasite Value, Price, and Jewelry Information
Marcasite has a long history of use as a decorative and jewelry material. However, this brassy colored, metallic stone is quite brittle and seldom…
Cinnabar Value, Price, and Jewelry Information
Magnificent red cinnabar is extremely soft and fragile, so faceted material is rare. It’s cut primarily for collectors and carvings.
Aragonite Value, Price, and Jewelry Information
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,…
Chrysocolla Value, Price, and Jewelry Information
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 Value, Price, and Jewelry Information
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…
Charoite Value, Price, and Jewelry Information
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 Value, Price, and Jewelry Information
Chrysoprase is apple-green chalcedony that derives its color from nickel. Its hardness and striking color make it a popular gemstone for jewelry…
Magnesite Value, Price, and Jewelry Information
Gems of completely transparent magnesite are both rare and beautiful. The huge birefringence is obvious even in small stones, and larger gems…
Freshwater Pearls Value, Price, and Jewelry Information
Like their marine cousins, many freshwater mollusks can produce pearls. However, this rarely occurs in nature. Today, the majority of pearls…
Moonstone Value, Price, and Jewelry Information
Found all over the world, moonstone is prized for its blue to white adularescence — a billowy, moonlight-like sheen. Despite being somewhat…
Ammolite Value, Price, and Jewelry Information
Ammolite is a rare, iridescent, gem-quality material cut from the fossilized shells of extinct sea creatures. Found only in the Bearpaw Formation…
Oregon Sunstone Value, Price, and Jewelry Information
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…
Malaya or Malaia Garnet Value, Price, and Jewelry Information
Malaia or malaya garnets are typically light to dark, slightly pinkish orange, reddish orange, or yellowish orange in color. This a popular…
Mali Garnet Value, Price, and Jewelry Information
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 Value, Price, and Jewelry Information
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 Value, Price, and Jewelry Information
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,…
Lapis Lazuli Value, Price, and Jewelry Information
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 Value, Price, and Jewelry Information
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 Value, Price, and Jewelry Information
Malachite is one of the most popular and beautiful of decorative stones. lts rich, patterned coloration in shades of green is unique among gems.…
Chalcedony Value, Price, and Jewelry Information
Technically, chalcedony (kal SED’ uh nee) is any form of microcrystalline or cryptocrystalline quartz, (meaning any form of quartz whose crystals…
Agate Value, Price, and Jewelry Information
Agate is a variety of chalcedony that exists in many colors and is often commercially dyed. Agate is distinguished by having multiple colors.…
Obsidian Value, Price, and Jewelry Information
Obsidian is an attractive material and displays a wide variety of appearances. Snowflake obsidian, with spherulites of cristobalite, is widely…
Topaz Value, Price, and Jewelry Information
The traditional November birthstone, topaz is a popular gem. Although frequently associated with golden yellow as well as blue, it can be found…
Sapphire Value, Price, and Jewelry Information
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…
Corundum Value, Price, and Jewelry Information
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…
Understanding Gem Synthetics, Treatments, and Imitations, Part 5: Gemstone Treatments
Identifying gemstone treatments is difficult even for experienced gemologists. Learn about the many different ways gem color and clarity are…
Understanding Gem Synthetics, Treatments, And Imitations, Part 2: Crystal Growth
Learn about the different crystal growth methods used to artificially create gemstones in laboratories.
Understanding Gem Synthetics, Treatments, And Imitations, Part 3: Synthetic Diamond
Learn about synthetic diamond creation and the challenges buyers face determining whether a diamond is natural or artificial.
Understanding Gem Synthetics, Treatments, And Imitations, Part 4: Synthetic Gemstone Guide
Many varieties of gems besides diamond can be created in the laboratory. Our synthetic gemstone guide covers many examples and explains their…
Anorthite Value, Price, and Jewelry Information
Anorthite is the most calcic of the plagioclases, and sometimes makes up a distinctive rock known as anorthosite, which has been extensively studied.…
Bytownite Value, Price, and Jewelry Information
Bytownite is found in basic plutonic rocks, some metamorphic rocks, and meteorites.
Andesine Value, Price, and Jewelry Information
These feldspars are rarely encountered in gem form. Andesine’s occurrence is widespread throughout the world, in a great variety of rock types…
Oligoclase Value, Price, and Jewelry Information
Oligoclase gems are feldspars that are part of a solid state series between albite and anothrite.
Albite Value, Price, and Jewelry Information
Albite, usually colorless but sometimes yellow, pink, gray or reddish. Translucent albite is sometime colored green by chrome jadeite. It is…
Peristerite Value, Price, and Jewelry Information
Peristerite is primarily oligoclase with a complex mixture of feldspars. It has iridescence that is either blue or white.
Perthite Value, Price, and Jewelry Information
Perthite is a blend of microcline, albite and oligoclase. It is usually brown and white. May have gold or white iridescence.
Sanidine Value, Price, and Jewelry Information
Sanidine is a mineral of volcanic rocks, rarely considered a gem. While occasionally brown or yellow, most examples are colorless.
Orthoclase Value, Price, and Jewelry Information
Orthoclase is best known for moonstone. It is occasionally a transparent, faceted gem. Note that moonstone is occasionally a labradorite.
Amazonite Value, Price, and Jewelry Information
Amazonite is a variety of microcline, which is itself a variety of feldspar.
Feldspar Value, Price, and Jewelry Information
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…
Rhodolite Garnet Value, Price, and Jewelry Information
Rhodolites are purplish red garnets, a blend between almandine and pyrope in composition. These durable gems have become popular jewelry stones.…
Zunyite Value, Price, and Jewelry Information
An overview on Zunyite Jewelry and Gemstones. Covers details and essential information on the physical properties and characteristics of Zunyite…
Zincite Value, Price, and Jewelry Information
Zincite is a very rare mineral, essentially restricted to one important locality. Well, terminated crystals were found only up to about 3-4 inches,…
Wilkeite Value, Price, and Jewelry Information
An overview on Wilkeite Jewelry and Gemstones. Covers details and essential information on the physical properties and characteristics of Wilkeite…
Weloganite Value, Price, and Jewelry Information
An overview on Weloganite Jewelry and Gemstones. Covers details and essential information on the physical properties and characteristics of…
Wardite Value, Price, and Jewelry Information
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…
Wollastonite Value, Price, and Jewelry Information
Interesting cabochons have been cut from wollastonite, especially from the fibrous material (which yields catseye stones) and the reddish material…
Villiaumite Value, Price, and Jewelry Information
Villiaumite is seldom discussed among collectors of rare gemstones because until recently no facetable material was known. The material from…
Ulexite Value, Price, and Jewelry Information
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…
Vanadinite Value, Price, and Jewelry Information
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…
Tremolite Value, Price, and Jewelry Information
It is possible to misidentify tremolite, mistaking it for other amphiboles. Hexagonite is the rarest of the gem varieties of tremolite. If tremolite…
Taafeite Value, Price, and Jewelry Information
Taaffeite reacts to most gemological tests like mauve-colored spinel, but can be distinguished on the basis of its birefringence. Additional…
Talc Value, Price, and Jewelry Information
An overview on Talc Jewelry and Gemstones. Covers details and essential information on the physical properties and characteristics of Talc gemstones.…
Tantalite Value, Price, and Jewelry Information
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 Value, Price, and Jewelry Information
Strontianite is a collector’s oddity, with no spectacular properties to recommend it. Colors are usually pale and there is little fire; in addition,…
Tektite Value, Price, and Jewelry Information
Tektites were first discovered in 1787 in Czechoslovakia (then Moravia) near the River Moldau, hence the name moldavite. It has been argued…
Tephroite Value, Price, and Jewelry Information
Tephroite is generally reddish brown and barely translucent. However, it takes a good polish and is massive enough to make good cabochons. Only…
Thomsonite Value, Price, and Jewelry Information
Thomsonite cabochons take a high polish but are somewhat brittle. These are especially lovely when a pinkish gray eyelike pattern is present,…
Stichtite Value, Price, and Jewelry Information
Stichtite is not facetable, but the pink color is quite striking in cabochons. Cut stones are especially beautiful when there are other minerals…
Stolzite Value, Price, and Jewelry Information
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 Value, Price, and Jewelry Information
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 Value, Price, and Jewelry Information
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…
Spurrite Value, Price, and Jewelry Information
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 Value, Price, and Jewelry Information
Simpsonite is an extremely rare gemstone. The material from Western Australia is bright yellow-orange and very beautiful. The mineral is hard…
Sinhalite Value, Price, and Jewelry Information
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,…
Sillimanite Value, Price, and Jewelry Information
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 Value, Price, and Jewelry Information
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 Value, Price, and Jewelry Information
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,…
Serpentine Value, Price, and Jewelry Information
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. …
Sellaite Value, Price, and Jewelry Information
An overview on Sellaite Jewelry and Gemstones. Covers details and essential information on the physical properties and characteristics of Sellaite…
Senarmontite Value, Price, and Jewelry Information
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 Value, Price, and Jewelry Information
Samarskite is a very heavy material from which lustrous black to brownish cabochons are sometimes cut as curiosities. The material is rather brittle…
Pyrophyllite Value, Price, and Jewelry Information
Pyrophyllite resembles talc in many ways and is indistinguishable by eye from soapstone. Chemical tests are needed to distinguish them. North…
Pyrite Value, Price, and Jewelry Information
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…
Pyrrohotite Value, Price, and Jewelry Information
An overview on Pyrrhotite Jewelry and Gemstones. Covers details and essential information on the physical properties and characteristics of…
Pumpellyite Value, Price, and Jewelry Information
The gem variety of pumpellyite, chlorastrolite, is best known from the Lake Superior district of the United States. It typically forms aggregates…
Prosopite Value, Price, and Jewelry Information
An overview on Prosopite Jewelry and Gemstones. Covers details and essential information on the physical properties and characteristics of…
Powellite Value, Price, and Jewelry Information
An overview on Powellite Jewelry and Gems. Covers details and essential information on the physical properties and characteristics of Powellite…
Prehnite Value, Price, and Jewelry Information
Prehnite is popular as a cabochon material among hobbyists because of its lovely green and blue-green to yellow colors. Completely transparent…
Purpurite Value, Price, and Jewelry Information
This material is never transparent and is too soft for wear. However, cabochons are a magnificent purplish rose hues that have essentially no counterpart…
Parisite Value, Price, and Jewelry Information
An overview on Parisite Jewelry and Gemstones. Covers details and essential information on the physical properties and characteristics of Parisite…
Pentlandite Value, Price, and Jewelry Information
Pentlandite resembles other yellowish metallic minerals and is cut by collectors as a curiosity. The cut stones are quite attractive but too soft…
Pargasite Value, Price, and Jewelry Information
The amphibole group is very large and extremely complex and contains numerous distinct species that vary subtly in chemistry and physical properties.…
Periclase Value, Price, and Jewelry Information
Periclase has been synthesized in large masses in the laboratory, but these have no market significance. A faceted natural periclase would be…
Neptunite Value, Price, and Jewelry Information
An overview on Neptunite Jewelry and Gemstones. Covers details and essential information on the physical properties and characteristics of…
Natrolite, Mesolite, Scolecite Value, Price, and Jewelry Information
All three minerals are fibrous or elongated zeolite minerals. Faceted gems are almost always elongated emerald cuts or step-cuts.
Nepheline Value, Price, and Jewelry Information
A variety called elaeolite is red, green, brown, or gray, massive or in crystals filled with minute inclusions. These inclusions produce…
Nambulite Value, Price, and Jewelry Information
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 Value, Price, and Jewelry Information
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 Value, Price, and Jewelry Information
Monazite may be partially metamict, with N=1.79. Stones can be an attractive yellow or brown color but are usually small.
Mimetite Value, Price, and Jewelry Information
Transparent mimetite crystals are extremely rare, and very few have ever been faceted. Cabochons with rich orange and yellow colors have been…
Mordenite Value, Price, and Jewelry Information
Compact, fibrous material is cabbed because the fibers provide a chatoyancy that sometimes yields weak catseyes. Coloration in the material…
Meliphanite Value, Price, and Jewelry Information
Meliphanite is an extremely rare gemstone, and perhaps fewer than 5-10 faceted stones have ever been cut.
Manganotantalite Value, Price, and Jewelry Information
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 Value, Price, and Jewelry Information
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.…
Linarite Value, Price, and Jewelry Information
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…
Lepidolite Value, Price, and Jewelry Information
Reddish granular or massive lepidolite is usually slabbed for ornamental purposes, such as ashtrays paperweights, and bookends. Faceted micas…
Lawsonite Value, Price, and Jewelry Information
Lawsonite is extremely rare as a faceted stone, seldom reported and generally unavailable.
Langbeinite Value, Price, and Jewelry Information
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 Value, Price, and Jewelry Information
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…
Kornerupine Value, Price, and Jewelry Information
Star kornerupine also has been found (Mogok, Myanmar) but is very rare. Kornerupine is generally dark brown or green and not very attractive…
Kämmererite Value, Price, and Jewelry Information
Kämmererite is a beautiful but rare mineral. It is micaceous; consequently, it is extraordinarily difficult to facet, which has severely limited…
Inderite Value, Price, and Jewelry Information
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…
Huebnerite Value, Price, and Jewelry Information
It should not be difficult to find numerous small faceted huebnerites among larger gemstone collections. Certainly ample material exists to…
Howlite Value, Price, and Jewelry Information
Howlite is always opaque in nodules; it is an abundant material and easy to acquire. Sometimes it contains black, threadlike impurities resembling…
Holtite Value, Price, and Jewelry Information
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 Value, Price, and Jewelry Information
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…
Gaylussite Value, Price, and Jewelry Information
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…
Gadolinite Value, Price, and Jewelry Information
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…
Fergusonite Value, Price, and Jewelry Information
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 Value, Price, and Jewelry Information
Euxenite is seldom seen in collections. Most collectors would not regard the mineral as facetable, but transparent fragments and areas of crystals…
Ettringite Value, Price, and Jewelry Information
Ettringite is not generally facetable; any cut stone would be considered an extreme rarity. South African material has yielded minute stones,…
Enstatite Value, Price, and Jewelry Information
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 Value, Price, and Jewelry Information
Dumortierite is a beautiful and very hard material, eminently suitable for jewelry. The cabochon material is the only generally known form, since…
Diopside Value, Price, and Jewelry Information
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…
Dickinsonite Value, Price, and Jewelry Information
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 Value, Price, and Jewelry Information
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,…
Cryolite Value, Price, and Jewelry Information
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 Value, Price, and Jewelry Information
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…
Canasite Value, Price, and Jewelry Information
The material usually seen on the market as “canasite” is purplish in color. It is frequently confused with another purplish material, a member…
Calcite Value, Price, and Jewelry Information
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 Value, Price, and Jewelry Information
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 Value, Price, and Jewelry Information
Breithauptite is a curiosity cut for collectors, although it could be worn with care in jewelry. The color is extremely lovely, a delicate reddish…
Cobaltite Value, Price, and Jewelry Information
Cabochons are interesting because of the lovely reddish metallic appearance of this mineral. Cut stones are infrequently seen and are cut only…
Beryl Value, Price, and Jewelry Information
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 Value, Price, and Jewelry Information
Chromite is shiny and black, and makes a curious-looking cabochon with no special attraction. Occasionally, a cabochon has a reddish color. The…
Childrenite Value, Price, and Jewelry Information
Cut childrenite is a great rarity, and all gems are small. Cut eosphorite is more abundantly available, though both materials are very scarce.…
Catapleiite Value, Price, and Jewelry Information
The only reported cut catapleiite is from Mte. Ste. Hilaire, Quebec, Canada, in the form of tiny colorless gems.
Bornite Value, Price, and Jewelry Information
Bornite is suitable only for cabochons. The bronzy color rapidly tarnishes in air to a magnificent iridescent color display, mostly purple, but…
Boleite Value, Price, and Jewelry Information
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…
Bismutotantalite Value, Price, and Jewelry Information
Extremely rare as a cut gem, even in very complete collections. Many of the minerals in the tantalite group have been faceted; bismutotantalite…
Bayldonite Value, Price, and Jewelry Information
Bayldonite is a nondescript greenish material that has been cut into cabochons by enterprising collectors of the unusual. Cut bayldonites are…
Analcime Value, Price, and Jewelry Information
Large colorless crystals of Analcime are a great rarity although small transparent crystals are abundant. Faceted gems are extremely rare and…
Actinolite Value, Price, and Jewelry Information
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 and Specifications
Gemstone color measurements are hard to make with conventional color-order systems. Learn how recent colorimetry tech advances have improved…
The Optical Spectrum and the Spectroscope
The spectroscope is a device that separates white light into an optical spectrum of component colors that can aid in gemstone and mineral identification.…
Understanding Color in Gemology
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 Value, Price, and Jewelry Information
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,…
Understanding Gem Synthetics, Treatments, And Imitations, Part 1: An Introduction
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 Value, Price, and Jewelry Information
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.
Labradorite Value, Price, and Jewelry Information
An overview on Labradorite Jewelry and Gemstones. Covers details and essential information on the physical properties and characteristics…
Quartz Value, Price, and Jewelry Information
An overview on Quartz Jewelry and Gemstones. Covers details and essential information on the physical properties and characteristics of a Quartz…
Diamond Value, Price, and Jewelry Information
Diamond is the most romanticized and heavily marketed of all gemstones. Nearly every jewelry establishment handles diamonds, even if it has no…
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