Gemstone Encyclopedia

Actinolite is a member of a series that contains varying amounts of ir...

Although adamite occurs in many localities, it's very rarely cut as a ...

Agate is a variety of chalcedony that exists in many colors and is oft...

Albite, usually colorless but sometimes yellow, pink, gray or reddish....

“Emerald by day, ruby by night,” alexandrite is well known for display...

Bright, silvery metallic cabochons of algodonite and domeykite are att...

Almandine is perhaps the most common garnet species. Forming series wi...

A green to blue-green variety of microcline, amazonite makes a wonderf...

Amber is the hardened resin of ancient pine trees. This organic substa...

Amblygonite gems are usually pale straw yellow. Although they are too ...

Amethyst is crystalline quartz in colors ranging from pale lilac to de...

Ametrine is a variety of quartz that displays bands of both amethyst p...

Ammolite is a rare, iridescent, gem-quality material cut from the foss...

Large colorless crystals of Analcime are a great rarity although small...

Anatase occurs in many beautiful colors, such as deep indigo and amber...

Strongly pleochroic, andalusite can show shades of green, brown, and r...

These feldspars are rarely encountered in gem form. Andesine's occurre...

Andradite is one of the most sought after garnet species. Although mor...

Although anglesites with pale colors can show great dispersion and bri...

Rare and difficult to cut, anhydrite is seldom faceted. However, this ...

Anorthite is the most calcic of the plagioclases, and sometimes makes ...

Although too brittle for most jewelry use, properly cut apatite gems a...

Although not suitable for jewelry, apophyllite is a popular collector'...

Named after the color of sea water, aquamarine is the blue to blue-gre...

Aragonite is more commonly found as a constituent of pearl and shell n...

Soft and brittle, rare augelites are difficult to cut and unsuitable f...

When faceted, the members of the axinite mineral group are usually int...

Collectors prize deep blue azurite crystals, but faceted gems are extr...

Massive white barite (also called known as baryte) looks like marble a...

Bayldonite is a nondescript greenish material that has been cut into c...

With dispersion higher than diamond and sapphire blue body color, beni...

The beryls are among the most popular, and also the most expensive, of...

Difficult to facet and typically colorless, beryllonite is a rare coll...

Extremely rare as a cut gem, even in very complete collections. Many o...

Also known as heliotrope, bloodstone is the traditional March birthsto...

Cut boleite is strictly for collectors, since it is soft and very rare...

With light blue and green colors, no cleavage, and high hardness, bora...

Bornite is suitable only for cabochons. The bronzy color rapidly tarni...

Brazilianite's lovely green to yellow colors make it a must for gem co...

Breithauptite is a curiosity cut for collectors, although it could be ...

Brookite usually occurs in very dark colors, transparent only in small...

Brucites are extremely difficult to cut. Although too soft for jewelry...

Bustamite is very similar in appearance and properties to rhodonite. T...

Bytownite is found in basic plutonic rocks, some metamorphic rocks, an...

Several species of marine mollusks produce stony growths called calcar...

Calcite is common and abundant throughout the world. The material has ...

The material usually seen on the market as “canasite” is purplish in c...

Cancrinite is one of the most attractive of all opaque or translucent ...

The best-known and generally least expensive variety of chalcedony is ...

Cassiterite is a durable gemstone with tremendous dispersive fire, esp...

The only reported cut catapleiite is from Mte. Ste. Hilaire, Quebec, C...

Soft, fragile, and hard to cut, celestite or celestine is seldom seen ...

A little-known gem material of truly exquisite color, sky-blue cerulei...

As beautiful as a diamond, a faceted cerussite actually has higher dis...

Although faceting chabazite isn't too difficult, it's too soft for jew...

Technically, chalcedony (kal SED' uh nee) is any form of microcrystall...

Chambersite is an exceedingly rare mineral. Although it has properties...

With light to medium dark purple colors and swirling patterns, charoit...

One of the most prized ornamental materials in China, chicken-blood st...

Cut childrenite is a great rarity, and all gems are small. Cut eosphor...

Chiolite makes a challenging gem. It's difficult to cut, extremely rar...

Chromite is shiny and black, and makes a curious-looking cabochon with...

Although many gems show a cat’s eye effect, when the term “cat’s eye” ...

Pure blue chrysocolla is extremely soft but interesting to gem collect...

Marketed as "Gem Silica" this relatively rare, blue to blue-green, opa...

Chrysoprase is apple-green chalcedony that derives its color from nick...

Magnificent red cinnabar is extremely soft and fragile, so faceted mat...

Citrine is the yellow to red-orange variety of crystalline quartz. Cle...

Clinochlore is a family of minerals in the chlorite group. To date, on...

Cabochons are interesting because of the lovely reddish metallic appea...

Colemanite is an abundant mineral, and transparent material isn’t rare...

Any stone that changes color under different types of light is a rare ...

Color change sapphires are those that change color between light sourc...

Coral is the external skeleton of a tiny, plant-like marine animal cal...

The crystal structure of cordierite has many similarities to that of b...

Next to diamond, corundum is the hardest mineral known and is very com...

Although covellite has attractive blue colors and shows iridescence, t...

Probably fewer than a dozen creedite gems have ever been faceted. This...

Lovely saffron-colored crocoite is quite a rare mineral. Although too ...

Cut cryolite is somewhat translucent, and has a "sleepy" look. The cut...

One of the rarest of all facetable gems, cut cuprites can show magnifi...

A very durable gemstone, danburite is an excellent choice for jewelry ...

Datolite is a popular collector’s mineral. Polished sliced nodules can...

One of the rarest garnet varieties, demantoid can have a green color t...

Diamond is the most romanticized and heavily marketed of all gemstones...

Diaspore is hard enough to make a durable jewelry stone, but the typic...

This mineral is seldom even mentioned in the gem literature because it...

Violane has been used for beads and inlay—transparent material is alwa...

Dioptase has a beautiful, emerald-like green color. Although this mine...

Although transparent dolomite crystals are fairly abundant and popular...

Dumortierite is a beautiful and very hard material, eminently suitable...

A relative newcomer to the world of gemstones, ekanite is rare and usu...

Emerald has been synonymous with the color green since ancient times. ...

Most gem enstatites have indices in the range 1.663-1.673. The brown a...

Faceted eosphorites in pale colors are quite attractive and easy to cu...

The epidote mineral supergroup contains many related species of intere...

Ettringite is not generally facetable. Any cut stone would be consider...

Although hard enough to be worn safely in jewelry, euclase in beautifu...

Although lapidaries can cut cabochons and decorative objects from mass...

Euxenite is seldom seen in collections. Most collectors would not rega...

Feldspars are the most common minerals at the Earth's surface. In fact...

This mineral is not abundant and is known from various localities. Cab...

Although too fragile for most jewelry use, fluorites are often faceted...

Like their marine cousins, many freshwater mollusks can produce pearls...

Friedelite is not abundant, and gem-quality material is rarely seen ev...

This is not a terribly attractive gemstone, but faceted gems would be ...

Gahnospinel is a solid-state solution between spinel and gahnite.

Although commonly associated with the color red, garnets can be found ...

This mineral is very hard to cut because of extreme softness and cleav...

Glass has been used in jewelry for thousands of years. By itself, glas...

A rather rare mineral, lovely blue-green grandidierite is seldom seen ...

Grossular garnets come in almost every color, even colorless, except b...

Gypsum is one of the most abundant minerals, but gem-quality crystals ...

Although hard enough for jewelry use, rare hambergite is a gem for col...

One of the major mineral constituents of lapis lazuli, haüyne is rarel...

Heliodor is a member of the beryl family. This stone is known for its ...

Hematite has a long history of use as a pigment. As a gemstone, this m...

Massive hemimorphite can have a very delicate, blue color. However, it...

Herderite is a rare collector's gem, especially in larger sizes. Altho...

Also known as the “cinnamon stone,” hessonite is the yellow-orange to ...

Hodgkinsonite is one of the rarest of all collector gems. Cut stones a...

This mineral was first noted in 1937 but was not described in detail u...

Howlite is always opaque in nodules; it is an abundant material and ea...

It should not be difficult to find numerous small faceted huebnerites ...

Clinohumites and chondrodites can make beautiful gemstones with rich c...

Hureaulite can show rich and lively pink, rose, and orange colors. How...

Hurlbutite is an extremely rare mineral. Minute, colorless faceted sto...

Hydrogrossular differs from the other garnets in that it is never tran...

Hyperitdiabas is one of the most outstanding minerals I have encounter...

Idocrase is one of the lesser known and more beautiful collector gems....

Inderite is very soft and difficult to cut, and only a few stones have...

This stone, which represents one of the few relatively available and a...

One of two distinct minerals commonly known as jade, jadeite is the ra...

Jasper is an opaque, solid or patterned variety of cryptocrystalline q...

Jeremejevite would make a durable and attractive jewelry stone, but th...

Historically a popular black gem, jet has declined in popularity in mo...

Star kornerupine also has been found (Mogok, Myanmar) but is very rare...

Kurnakovite is difficult to cut, inadvisable to wear, and usually colo...

Kyanite is very rare as a faceted gem, especially if free from inclusi...

A beautiful but rare mineral, kämmererite is extraordinarily difficult...

An overview on Labradorite Jewelry and Gemstones. Covers details and e...

This material is nondescript and is cut solely as a curiosity. The gem...

Lapis lazuli has been used since ancient times and remains popular tod...

Laserblue is a rare, synthetic glass. It's hard for glass but easy to ...

Lawsonite is extremely rare as a faceted stone, seldom reported and ge...

Lazulite makes a magnificent, deep blue gemstone. Although the mineral...

Too soft for jewelry use, legrandite is a popular collector’s mineral ...

Reddish granular or massive lepidolite is usually slabbed for ornament...

Although abundant in various lava rocks, leucite is extremely rare in ...

The blue color of linarite is magnificent, and it is a pity that large...

Ludlamite has a lovely green color, but cut stones are extremely rare....

Transparent, gem-quality magnesite is rare and beautiful, with colors ...

Malachite is a beautiful decorative stone. Its rich, patterned colorat...

Malaia or malaya garnets are typically light to dark, slightly pinkish...

One of the rarer varieties in the garnet group, Mali garnet is a blend...

While the colors of spessartite garnet gemstones cover a wide range of...

Manganotantalite makes a spectacular red brown gem that is a very rare...

Marcasite has a long history of use as a decorative and jewelry materi...

Meliphanite is an extremely rare gemstone, and perhaps fewer than 5-10...

Mellite is a rare and unusual organic gemstone. Although soft and frag...

Microcline is a variety of feldspar. The only microcline you are likel...

Ranging in color from pale yellow to brown, reddish, and green, microl...

Very rare milarite crystals can occur in green and yellow colors. Tran...

Millerite has a rich, attractive yellow color. Massive millerites can ...

Transparent mimetite crystals are extremely rare, and very few have ev...

An olive to bottle-green natural glass, moldavite is a rare material p...

Monazite may be partially metamict, with N=1.79. Stones can be an attr...

Found all over the world, moonstone is prized for its blue to white ad...

Compact, fibrous material is cabbed because the fibers provide a chato...

A member of the beryl family, morganite shows a range of pink colors d...

The color of Namibian nambulite is a striking orange-red, very intense...

All three minerals are fibrous or elongated zeolite minerals. Faceted ...

Glass comes in several natural forms. All are used in jewelry.

A variety called elaeolite is red, green, brown, or gray, massive or i...

Nephrite is one of the two distinct minerals commonly known as jade. W...

An overview on Neptunite Jewelry and Gemstones. Covers details and ess...

Niccolite’s delicate peachy red color and metallic luster looks beauti...

Obsidian is the most common form of natural glass and occurs in many a...

Oligoclase gems are feldspars that are part of a solid state series be...

For millennia, artisans have carved intricate cameos from black-and-wh...

Opals are in a class by themselves. As a species, opal is so unique it...

While feldspar sunstones from sources around the world have been used ...

Orthoclase is best known for moonstone. It is occasionally a transpare...

Padparadscha is a light to medium toned pink-orange to orange-pink hue...

Until 2001, only three painite crystals were known to exist. Since the...

Although marketed as “angel skin opal,” “rock wood,” and “mountain lea...

Cerulean blue papagoite crystals are too small for faceting. However, ...

Discovered in 1989, paraíba tourmalines are among the world’s most pri...

The amphibole group is very large and extremely complex and contains n...

An overview on Parisite Jewelry and Gemstones. Covers details and esse...

Pearls are the only gems found within living creatures, both salt and ...

Fibrous pectolite has long been a curiosity for gem collectors. Compac...

Pentlandite resembles other yellowish metallic minerals and is cut by ...

Periclase has been synthesized in large masses in the laboratory, but ...

The modern August birthstone, peridot has been prized as a jewelry sto...

Peristerite is primarily oligoclase with a complex mixture of feldspar...

Perthite is a blend of microcline, albite and oligoclase. It is usuall...

Gem-quality, colorless, facetable petalite is rare and desirable to co...

Rare phenakite is a very hard gem material suitable for jewelry. Usual...

Rare phosgenite typically shows pale colors. This material is difficul...

Renowned for its delicate blue-green shades, phosphophyllite’s beauty ...

Colorless pollucites lack fire when cut and are usually small. However...

An overview on Powellite Jewelry and Gems. Covers details and essentia...

Prehnite is popular as a cabochon material among hobbyists because of ...

Prosopite is usually a nondescript mineral with no gem significance. H...

A few almandine/pyrope garnets from the US will change with treatment ...

Proustite crystals have magnificent red colors and good brilliance. Al...

The gem variety of pumpellyite, chlorastrolite, is best known from the...

Purpurite is too soft for jewelry wear and never transparent. Neverthe...

Deep red pyrargyrite occurs in a number of localities in well-formed b...

Pyrite is more commonly known as fool’s gold and is familiar to nearly...

Pyrope always occurs in series with other garnet species. Common, dark...

Pyrophyllite resembles talc in many ways and is indistinguishable by e...

Pyroxmangite grains are rare, seldom clean enough to facet, and diffic...

An overview on Pyrrhotite Jewelry and Gemstones. Covers details and es...

An overview on Quartz Jewelry and Gemstones. Covers details and essent...

Quartzite is a rock made up of tightly packed quartz grains. Sometimes...

Although this common arsenic sulfide mineral occurs worldwide, cut gem...

Originally known as bixbite, red beryl is one of the rarest, most desi...

Rhodizite is tough enough to make an excellent jewelry stone. However,...

Beautiful rose red to pink rhodochrosite crystals are popular with min...

Rhodolites are purplish red garnets, a blend between almandine and pyr...

Ranging in color from pink to a fine rose red, rhodonite is a popular ...

A popular variety of colored quartz, rose quartz makes a durable jewel...

Rubellites are tourmalines with reasonably saturated dark pink to red ...

One of the most popular traditional jewelry stones, ruby is exceptiona...

Though perhaps best known as inclusions within other gems, rutile crys...

Although pearls are one of humanity’s most ancient gems, natural under...

Samarskite is a very heavy material from which lustrous black to brown...

Sanidine is a mineral of volcanic rocks, rarely considered a gem. Whil...

Few gems have held our attention over millennia as well as sapphire. T...

Sapphirines are durable but very rare gemstones. Although named after ...

Sarcolite is an extremely rare mineral. Tiny, colorless to “fleshy pin...

Although not well known, scapolite would make an attractive gem materi...

Large, faceted scheelites are among the most beautiful of all collecto...

With lovely colors and intense pleochroism, faceted scorodite is a pri...

An overview on Sellaite Jewelry and Gemstones. Covers details and esse...

Senarmontite is a rare mineral, restricted in occurrence to the presen...

To date, only one locality — Mont St. Hilaire, Quebec, Canada — has pr...

The gem material known as serpentine actually encompasses several rela...

Shattuckite is often mixed with quartz, and data often reported for pr...

Shortite is an exceedingly rare, not overly attractive mineral. Cut ge...

Siderite is difficult to cut, but this light brown collector's gem has...

The fibrolite from Burma and Sri Lanka is well known to gem collectors...

Simpsonite is an extremely rare gemstone. The material from Western Au...

Long thought to be brown peridot, sinhalite was investigated in 1952 a...

Smaltite is a collectors oddity, cut only as cabochons. It is seldom s...

Smithsonite occurs across the globe, but facetable crystals are extrem...

Smoky quartz comes in every shade of brown, from a light tan to nearly...

Typically blue, durable, and easy to cut, sodalite is highly desired b...

Sogdianite is an extremely rare mineral, suitable for cabochons. The c...

Usually orange to reddish brown, gem-quality spessartite or spessartin...

Sphalerite occurs in many colors. With a dispersion over three times t...

Sphene, also known as titanite, has rich body colors, strong trichrois...

Spinel is an important gem historically because it has been confused w...

Extraordinarily difficult to cut, spodumene has several colorful varie...

An attractive but uncommon mineral, spurrite has seldom been cut as a ...

Star sapphire is a type of sapphire that displays asterism, a star-lik...

Staurolite crystals in opaque cross shapes are popular gemstones. Howe...

Rare stibiotantalite possesses an interesting mix of physical and opti...

Stichtite is not facetable, but the pink color is quite striking in ca...

Stolzite is a rare mineral; much rarer than wulfenite and usually occu...

Strontianite is a collector’s oddity, with no spectacular properties t...

What is the color of sugilite? Grape jelly purple is a good descriptio...

Although sulfur is very abundant, facetable material is not. Sulfur is...

Sunstones contain hematite or goethite inclusions, which reflect light...

Taaffeite reacts to most gemological tests like mauve-colored spinel, ...

An overview on Talc Jewelry and Gemstones. Covers details and essentia...

Tantalite is too dark to be of use as a faceted gem but is sometimes c...

Tanzanite has had a rapid rise to prominence among jewelers and gem en...

Tektite is a natural glass formed from the ejected debris of meteorite...

Tephroite is generally reddish brown and barely translucent. However, ...

For a long time, rare thaumasite crystals — pale, fragile, and with li...

Thomsonite cabochons take a high polish but are somewhat brittle. Thes...

Crocidolite, (blue asbestos,) alters to quartz, but while retaining it...

The traditional November birthstone, topaz is a popular gem. Although ...

Tourmaline is a name applied to a family of related minerals with wide...

It is possible to misidentify tremolite, mistaking it for other amphib...

Triphylite is one of the world's rarest gems. The IGS had the extraord...

An emerald-green variety of grossular garnet, tsavorite is one of the ...

Gem collectors prize tugtupite for its rich colors and intense reactio...

With striking sky blue to blue-green colors, turquoise has been prized...

The fibrous material cuts interesting catseye cabochon gems, but they ...

Always a dark, rich green color, uvarovite is one of the rarest member...

A faceted vanadinite may be considered a tremendous rarity. Fewer than...

With beautiful green to blue-green colors and interesting patterns, va...

Villiaumite is seldom discussed among collectors of rare gemstones bec...

Vivianite is so fragile and soft, any faceted gems would be difficult ...

Väyrynenite is a very rare mineral. Crystals as well as faceted gemsto...

Wardite is another of the many phosphates that have been cut by collec...

Wavellite is a very attractive mineral, well-known to collectors. Its ...

An overview on Weloganite Jewelry and Gemstones. Covers details and es...

Seldom seen even in mineral collections, whewellite is very rarely fac...

An overview on Wilkeite Jewelry and Gemstones. Covers details and esse...

Willemite is prized for its intense green fluorescence. Too fragile fo...

Easy to cut but too soft and fragile for jewelry, a faceted witherite ...

Interesting cabochons have been cut from wollastonite, especially from...

Although aesthetically magnificent wulfenite crystals are often too th...

Xonotlite is strong and can take a good polish. However, these gems ar...

Yugawaralite is a very rare colorless to pinkish zeolite mineral. Litt...

Small, cuttable crystals of very rare zektzerite are found only in a m...

Zincite is a very rare mineral. It’s also difficult to cut, which make...

Don’t be confused by the name. Zircon is a natural, magnificent, and u...

An overview on Zunyite Jewelry and Gemstones. Covers details and essen...