Joel E. Arem, Ph.D., FGA
ContributorDr. Joel E. Arem has more than 60 years of experience in the world of gems and minerals. After obtaining his Ph.D. in Mineralogy from Harvard University, he has published numerous books that are still among the most widely used references and guidebooks on crystals, gems and minerals in the world.
Co-founder and President of numerous organizations, Dr. Arem has enjoyed a lifelong career in mineralogy and gemology. He has been a Smithsonian scientist and Curator, a consultant to many well-known companies and institutions, and a prolific author and speaker. Although his main activities have been as a gem cutter and dealer, his focus has always been education. joelarem.com
Articles by Joel E. Arem, Ph.D., FGA
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...
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Jadeite Value, Price, and Jewelry Information
One of two distinct minerals commonly known as jade, jadeite is the rarer and harder variety. Rich green jadeite, known...
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Variscite Value, Price, and Jewelry Information
With beautiful green to blue-green colors and interesting patterns, variscite is a popular hobbyist material for cabochons.
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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...
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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...
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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...
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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...
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Eudialyte Value, Price, and Jewelry Information
Although lapidaries can cut cabochons and decorative objects from massive or translucent eudialyte crystals, transparent material suitable for faceting is...
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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....
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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...
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Bytownite Value, Price, and Jewelry Information
Although bytownite occurs throughout the world, this feldspar variety is rarely encountered in gem-quality condition.
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Villiaumite Value, Price, and Jewelry Information
A little-known and rare collector’s gemstone, villiaumite is very difficult to facet. Its toxicity also makes it inadvisable to handle...
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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...
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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...
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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...
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Morganite Value, Price, and Jewelry Information
A member of the beryl family, morganite shows a range of pink colors due to traces of manganese. Recently, this...
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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...
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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...
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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...
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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...
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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...
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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...
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Gemstone Optics: The Basics
Accurately measuring optical properties is critical for identifying gemstones. This article covers the basic terminology and concepts of gemstone optics....
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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...
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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....
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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...
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Apophyllite Value, Price, and Jewelry Information
Although not suitable for jewelry, apophyllite is a popular collector's piece. Perhaps the whitest of all gems, some cut specimens...
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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...
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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...
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Parisite Value, Price, and Jewelry Information
More well-known as rare inclusions in emeralds, parisite crystals are usually small and seldom faceted.
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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...
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Axinite Value, Price, and Jewelry Information
When faceted, the members of the axinite mineral group are usually intensely pleochroic, with rich brown and purple colors dominating....
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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...
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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...
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What is Gemstone Cleavage?
Gemstone cleavage is a break in a crystal along internal planes. Learn the science behind this and the difference between...
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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....
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Demantoid Garnet Value, Price, and Jewelry Information
One of the rarest garnet varieties, demantoid can have a green color that rivals emerald and a fire that exceeds...
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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...
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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...
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Tugtupite Value, Price, and Jewelry Information
Gem collectors prize tugtupite, the "Reindeer Stone," for its rich colors and intense reaction to ultraviolet light. Sporadically used in...
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Serandite Value, Price, and Jewelry Information
To date, only one locality — Mont St. Hilaire, Quebec, Canada — has produced facetable serandite. These extremely rare gems...
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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...
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Weloganite Value, Price, and Jewelry Information
Truly a collector’s gem, weloganite is very rare and seldom cut. This stone can show pale yellow colors.
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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...
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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 in...
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Cryolite Value, Price, and Jewelry Information
Typically colorless with a “sleepy” look, cryolite is rarely found in nature. Rough suitable for gem faceting is extremely scarce....
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Cobaltite Value, Price, and Jewelry Information
Cobaltite cabochons can have a lovely metallic luster. However, this gem material is very seldom faceted.
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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...
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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...
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Anorthite Value, Price, and Jewelry Information
The rarest plagioclase feldspar, anorthite is very rarely faceted.
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Datolite Value, Price, and Jewelry Information
Polished and sliced datolite nodules can show off very attractive colors. Datolite is a popular collector’s mineral, but faceted and...
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Rhodochrosite Value, Price, and Jewelry Information
Beautiful rose red to pink rhodochrosite crystals are popular with mineral collectors. Although very soft, opaque stones have been fashioned...
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Descriptive Crystallography for Gemologists
Crystallography is the study of crystalline solids. Learn the most common terms gemologists use to describe the structure of crystal...
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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...
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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...
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Kyanite Value, Price, and Jewelry Information
Kyanite’s physical properties make it very difficult to facet. However, it’s a popular collector’s gem, especially in sapphire-blue colors.
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Amazonite Value, Price, and Jewelry Information
A green to blue-green variety of microcline, amazonite makes a wonderful gemstone for cabbing and carving.
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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.
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Serpentine Value, Price, and Jewelry Information
The gem material known as serpentine actually encompasses several related mineral species. For millennia, people have cut serpentines into beautiful...
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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...
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Purpurite Value, Price, and Jewelry Information
Purpurite is too soft for jewelry wear and never transparent. Nevertheless, lapidaries have cut cabochons from this material with magnificent...
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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...
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Ludlamite Value, Price, and Jewelry Information
Ludlamite has a lovely green color, but cut stones are extremely rare. Large crystals of this phosphate mineral are known...
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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 accuracy....
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Oregon Sunstone Value, Price, and Jewelry Information
While feldspar sunstones from sources around the world have been used for carvings and cabochons, Oregon sunstone material has proven...
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Prosopite Value, Price, and Jewelry Information
Prosopite is usually a nondescript mineral with no gem significance. However, beautiful blue specimens are sometimes cut for jewelry.
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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...
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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...
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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. However,...
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Understanding Gemological Formulas
Gemological formulas identify the chemical composition of gems and minerals. Learn what the symbols, numbers, and parentheses mean.
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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...
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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...
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What is Gemstone Luster?
Gemstone luster describes how a gem's surface looks when it reflects light. Learn the common terms gemologists use for this...
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Herderite Value, Price, and Jewelry Information
Herderite is a rare collector's gem, especially in larger sizes. Although too soft for daily jewelry wear, this material is...
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Sodalite Value, Price, and Jewelry Information
Typically blue, durable, and easy to cut, sodalite is highly desired by hobbyists. Even stones that lack transparency make lovely...
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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....
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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...
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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...
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Tektite Value, Price, and Jewelry Information
Tektite is a natural glass formed from the ejected debris of meteorite impacts. Though most pieces are very small, some...
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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...
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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...
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Ametrine Value, Price, and Jewelry Information
Ametrine is a variety of quartz that displays bands of both amethyst purple and citrine yellow. These gems are typically...
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Kämmererite Value, Price, and Jewelry Information
A beautiful but rare mineral, kämmererite is extraordinarily difficult to facet. As a result, the availability of cut gems is...
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Opal Stones and Gems: Value, Price, and Jewelry Information
Opals are in a class by themselves. As a species, opal is so unique it has its own descriptive vocabulary....
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What is Moonstone Gemstone? Value, Price, and Color
Found all over the world, moonstone is prized for its blue to white adularescence — a billowy, moonlight-like sheen. Despite...
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Amethyst Value, Price, and Jewelry Information
Amethyst is crystalline quartz in colors ranging from pale lilac to deep reddish purple. The February birthstone makes a fine,...
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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...
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Garnet Value, Price, and Jewelry Information
Although commonly associated with the color red, garnets can be found in almost any color and are popular choices for...
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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...
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Almandine Garnet Value, Price, and Jewelry Information
Almandine is perhaps the most common garnet species. Forming series with pyrope and spessartine garnets, these gems occur in the...
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Spurrite Value, Price, and Jewelry Information
An attractive but uncommon mineral, spurrite has seldom been cut as a gemstone. However, it has the hardness and tenacity...
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Kurnakovite Value, Price, and Jewelry Information
Kurnakovite is difficult to cut, inadvisable to wear, and usually colorless. Consequently, faceted specimens are extremely rare.
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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...
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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...
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Obsidian Value, Price, and Jewelry Information
Obsidian is the most common form of natural glass and occurs in many attractive varieties. Since prehistoric times, people have...
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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...
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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...
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Coral Value, Price, and Jewelry Information
Coral is the external skeleton of a tiny, plant-like marine animal called the coral polyp. The structures that result from...
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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...
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Malachite Value, Price, and Jewelry Information
Malachite is a beautiful decorative stone. Its rich, patterned coloration in shades of green is unique among gems. Malachite's low...
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Charoite Value, Price, and Jewelry Information
With light to medium dark purple colors and swirling patterns, charoite is one of the few gemstones so distinctive that...
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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...
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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...
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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...
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Magnesite Value, Price, and Jewelry Information
Transparent, gem-quality magnesite is rare and beautiful, with colors ranging from colorless, white, and gray to a yellowish brown. This...
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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...
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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...
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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...
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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...
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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...
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Amber Value, Price, and Jewelry Information
Amber is the hardened resin of ancient pine trees. This organic substance is most well-known for the incredible inclusions of...
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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...
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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...
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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...
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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...
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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...
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Celestite Value, Price, and Jewelry Information
Soft, fragile, and hard to cut, celestite or celestine is seldom seen in gem collections. These gems are usually colorless...
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Lapis Lazuli Value, Price, and Jewelry Information
Lapis lazuli has been used since ancient times and remains popular today. This gemstone has been prized for its bright,...
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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...
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Tourmaline Value, Price, and Jewelry Information
Tourmaline is a name applied to a family of related minerals with widely varying properties. Tourmalines make very popular jewelry...
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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...
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Gemstone Treatment Codes
The AGTA has proposed the use of gemstone treatment codes to promote disclosure and a common language for these procedures....
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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...
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Pyrope Garnet Value, Price, and Jewelry Information
Pyrope always occurs in series with other garnet species. Common, dark red garnets are a mixture of almandine and pyrope....
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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...
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Gemstone Thermal Properties
Non-destructive tests are critical for gemologists trying to identify gems. Learn how measuring thermal properties, especially thermal inertia, can help....
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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...
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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...
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Emerald Value, Price, and Jewelry Information
Emerald has been synonymous with the color green since ancient times. A fine emerald is a truly breathtaking sight, and...
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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...
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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...
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Ruby and Sapphire Origins
Ruby and sapphire origins greatly affect the values of these prized gems. Learn where these stones occur and how inclusions...
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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...
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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...
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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...
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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...
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Saltwater Pearls Value, Price, and Jewelry Information
Although pearls are one of humanity’s most ancient gems, natural undersea beds of pearl-producing oysters now occur very rarely. Cultured...
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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...
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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...
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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...
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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...
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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...
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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...
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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....
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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....
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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,...
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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...
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Spessartite Garnet Value, Price, and Jewelry Information
Usually orange to reddish brown, gem-quality spessartite or spessartine garnets are somewhat rare. However, as blends with other garnet species,...
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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....
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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...
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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...
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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...
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Tsavorite Garnet Value, Price, and Jewelry Information
An emerald-green variety of grossular garnet, tsavorite is one of the most popular and expensive varieties of garnet. Suitable for...
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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...
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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...
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Citrine Value, Price, and Jewelry Information
Citrine is the yellow to red-orange variety of crystalline quartz. Clever marketing and the rise of “earth tone” fashions have...
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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...
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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,...
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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...
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Willemite Value, Price, and Jewelry Information
Willemite is prized for its intense green fluorescence. Too fragile for jewelry use, faceted specimens are extremely rare.
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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...
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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...
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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...
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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 and...
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What is Gemstone Luminescence?
Gemstone luminescence is a glow that occurs when certain stones are subjected to energy such as UV light. This effect...
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Thaumasite Value, Price, and Jewelry Information
For a long time, rare thaumasite crystals — pale, fragile, and with little to no fire — were interesting primarily...
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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...
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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 ore...
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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,...
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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...
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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...
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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...
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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...
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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...
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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...
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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...
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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...
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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 faceted...
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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...
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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...
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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...
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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...
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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...
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Hurlbutite Value, Price, and Jewelry Information
Hurlbutite is an extremely rare mineral. Minute, colorless faceted stones have been cut from fragments.
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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...
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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...
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Palygorskite Value, Price, and Jewelry Information
Although marketed as “angel skin opal,” “rock wood,” and “mountain leather,” palygorskite is neither opal, wood, nor leather. This unusual,...
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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.
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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...
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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...
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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...
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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....
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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...
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Spinel Value, Price, and Jewelry Information
Spinel is an important gem historically because it has been confused with other gemstones, especially ruby. Large red gems such...
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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...
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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...
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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...
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Understanding Gem Synthetics, Treatments, And Imitations, Part 2: Crystal Growth
Learn about the different crystal growth methods used to artificially create gemstones in laboratories.
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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.
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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...
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Sunstone Value, Price, and Jewelry Information
Sunstones contain hematite or goethite inclusions, which reflect light in parallel orientation and create a sparkling sheen in gold to...
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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...
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Oligoclase Value, Price, and Jewelry Information
Oligoclase gems are feldspars that are part of a solid state series between albite and anothrite.
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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...
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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.
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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...
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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....
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Orthoclase Value, Price, and Jewelry Information
Orthoclase is best known for moonstone. It is occasionally a transparent, faceted gem.
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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...
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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...
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Zincite Value, Price, and Jewelry Information
Zincite is a very rare mineral. It’s also difficult to cut, which makes faceted zincite one of the rarest of...
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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...
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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...
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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...
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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...
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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...
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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...
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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...
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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...
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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,...
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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...
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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...
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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...
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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...
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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...
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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...
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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...
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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...
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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,...
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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...
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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...
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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...
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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...
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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...
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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...
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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....
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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...
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Pyrrhotite Value, Price, and Jewelry Information
An overview on Pyrrhotite Jewelry and Gemstones. Covers details and essential information on the physical properties and characteristics of Pyrrhotite...
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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...
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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...
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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...
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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...
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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...
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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...
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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 Neptunite...
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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.
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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...
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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...
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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....
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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...
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Meliphanite Value, Price, and Jewelry Information
Meliphanite is an extremely rare gemstone, and perhaps fewer than 5-10 faceted stones have ever been cut.
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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...
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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....
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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 are...
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Lawsonite Value, Price, and Jewelry Information
Lawsonite is extremely rare as a faceted stone, seldom reported and generally unavailable.
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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...
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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...
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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...
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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...
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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...
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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...
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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...
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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...
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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,...
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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...
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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...
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Ettringite Value, Price, and Jewelry Information
Ettringite is not generally facetable. Any cut stone would be considered an extreme rarity.
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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...
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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...
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