Agate to Zircon
Adularia
Adularia is a variety of orthoclase feldspar that is colorless to milky in appearance. It is mineralogically a potassium, aluminum, silicate feldspar found in the Alps which can display a bluish sheen. This phenomenon is called adularescence....
Agate
Agate, a variety of chalcedony, occurs in many different colors and in all degrees of diaphaneity - although mainly opaque to translucent. There are many agate varieties named after specific locations where they were found or named after a physical characteristic as...
Alabaster
Alabaster is a name used for gypsum and calcite but has also been used to indicate selenite. These minerals are easily worked due to their low hardness and have been used to craft all sort of things from since antiquity. Think of sculptures, household items and, of...
Alexandrite
Alexandrite and Diamond Ring. Alexandrite, a chrysoberyl variety, possesses a distinct change of color when viewed under different (incandescent and fluorescent) light sources. The change in color is caused by trace amounts of chromium and vanadium. The amounts of...
Almandine
Almandine Garnet Ring. These deep purplish-red garnets were often featured in Victorian Jewelry. When they are cut en cabochon they are referred to as "carbuncles." [table id=62 responsive=collapse...
Amazonite
Amazonite, a variety of the microcline series of the feldspar group, gets its name from the Amazon River. A gridlike structure visable in amazonite gives the stone a faint sheen and makes it easily identifiable. Amazonite is always cut...
Amber
In the forest primeval, a creature calls…Its echo is heard for millions of years.Frozen in time; the drama unfolds--A death struggle painted in amber tears. Amber is the fossilized resin from ancient, extinct, pine trees and conifers which...
Amethyst
Amethyst is almost certainly the most coveted member of the quartz family. It has a color range from a deep purple with red flashes (known as Siberian amethyst) to a pale lilac with blue undertones which are termed Rose de France. These colors are the result of minor...
Ametrine
Ametrine is a variety of quartz consisting of both amethyst and citrine with zones of both purple and yellow. Most naturally occurring ametrine comes from Bolivia, with some from India and Brazil. Differentially heat treating amethyst can...
Andalusite
Andalusite var. Chiastolite. More InformationGems & Gemology: The Quarterly Journal of the Gemological Institute of America G&G Article...
Andradite
Andradite Garnet var. Demantoid.
Apatite
More InformationGems & Gemology: The Quarterly Journal of the Gemological Institute of America. G&G Article Index: ApatiteSummer 1962,...
Aquamarine
Aquamarine Ring. Aquamarine (from the Latin, "water from the sea") is, as the name suggests, a pale green bluish to medium dark blue member of the beryl family. Due to its lovely, limpid color and its durability aquamarine has been one of the most...
Aragonite
Aragonite is a naturally occurring crystal form of calcium carbonate and is a precipitate from salt and freshwater conditions. One form of aragonite occurs naturally in most mollusks. Crystallizing from calcium carbonate into orthorhombic translucent microscopic...
Aventurescence
Aventurescence is a phenomenon in gemstones whereby glittering reflections of small inclusions of hematite or goethite in feldspar or fuchsite or hematite in quartz, sparkle and shimmer.
Aventurine
Azurite
More InformationGems & Gemology: The Quarterly Journal of the Gemological Institute of America. G&G Article...
Azurmalachite
Sources Gem Reference Guide, Los Angeles: Gemological Institute of America, 1988. Pp. 22-23. Schumann, Walter. Gemstones...
Benitoite
More InformationGems & Gemology: The Quarterly Journal of the Gemological Institute of America. G&G Article Index: BenitoiteSummer 1953,...
Beryl
Beryl is a mineral family with a wide variety of colors, ranging from blue to red. The colors are produced by minor traces of elements in the beryllium silicate crystal lattice. When these traces are absent, the mineral is colorless. The two most important gemstones...
Biwa Pearl
Biwa pearls are a cultured pearl produced in a freshwater mussel native to Lake Biwa, Japan. Considered to be a non-nucleated pearl, they are produced by introducing 10 to 20 bits of mantle tissue from another mussel into incisions in the host mantle. The...
Bloodstone
Bloodstone Intaglio Signet Ring with a Coat of Arms Seal. Tiffany & Co. Who on this world of ours his eyesIn Aries opens shall we be wiseIf always on his hand there liesA Bloodstone. Bloodstone is a polycrystalline variety...
Cairngorm
Cairngorm is the name given to a citrine quartz variety with an amber or brown color traditionally mined in the Cairngorm Mountains in Scotland. During the Victorian period cairngorms were extensively used in traditional Scottish jewelry such as kilt ornaments, bonnet...
Calcareous Concretion
Calcareous concretions are pearl-like growths produced in mollusks that lack nacre. While still composed of calcite and aragonite, the crystals are much coarser. Some of these "pearls" may have a flame-like sheen on their surface. Calcareous concretions...
Calcite
Sources Gem Reference Guide, Los Angeles: Gemological Institute of America, 1988. Pp. 41-43. Schumann, Walter. Gemstones of the World, New York:...
Calcium Carbonate
Calcium carbonate is a primary component of the shells of marine mollusks and pearls. The outer shells of mollusks are composed of calcium crystals bound by conchiolin. The middle layer is formed by calcium carbonate hardened as crystalline calcite. The...
Carbuncle
A large almandine garnet that is cut en cabochon. These deep purplish-red garnets were popular in Victorian jewelry.
Carnelian
Carnelian Intaglio Ring. Carnelian (or cornelian) is the translucent red variety of chalcedony which in its turn is a form of cryptocrystalline quartz. It's been known and used since antiquity when it was sourced from the surfaces of the Egyptian and...
Cave Pearls
Cave pearls are not actually pearls, they are a calcareous concretion occurring in subterranean limestone caves. While they bear a resemblance to pearls, they have a porous texture. Cave pearls form when calcite crystallizes on a nucleus, similar to the...
Chalcedony
Chalcedony is cryptocrystalline quartz. It is semitransparent to opaque and, depending on its color, chalcedony is further divided into several varieties. History All varieties of chalcedony were very popular in Victorian Jewelry. Moss agate, known for its green...
Chlorastrolite
Chlorastrolite. Sources Gem Reference Guide, Los Angeles: Gemological Institute of America, 1988. Pp. 49-50.
Chrysoberyl
A 9.39 carat Cat’s Eye Chrysoberyl is the Star of this Vintage Style Ring. Cat's eye has the longest history of gems in the chrysoberyl family. It was treasured in Asia before the birth of Christ and became quite well known in Rome by the end of the First Century. In...
Chrysocolla
Chrysocolla is an intense blue-green to light blue variety of chalcedony. It can be translucent to semitransparent and is usually cut en cabochon. Tumbled Chrysocolla.
Chrysoprase
Chrysoprase is the name reserved for bright green cryptocrystalline quartz. It is a subvariety of chalcedony and owes its beautiful green color to the presence of nickel impurities in its crystal structure. The material was very popular in Victorian times when it was...
Cinnabar
French Japonesque Cinnabar, Diamond and Onyx Jabot Pin. Online Texts on CinnabarSome Cinnabar Deposits in Western Nevada by Knopf
Citrine
The yellow to golden variety of quartz, colored by trace elements of iron, is named citrine. The color of citrine closely resembles the color of the more expensive yellow topaz and consequently, citrine is sometimes marketed under various misnomers such...
Conch Pearls
Conch Pearls A conch pearl is not technically a pearl at all, but a white or pink (sometimes brown or yellow), non-nacreous, product of the saltwater giant conch or queen conch shell. Classified as a calcareous concretion, conch pearls are rare and generally found as...
Copal
Copal is a fossilized organic resin. This amorphous yellow to brownish material is often confused with amber, but amber is much older than copal. A test using acetone can separate amber and copal - copal will react immediately while amber will take longer to be...
Coque de Perle
Coque de perle, from the French for 'pearl shell' was a Georgian faux pearl carved from the East Indian nautilus shell. The central whorl of the convex part of the shell was cut away to form these delicate "eggshell pearls." Filled with cement to stabilize it, coque...
Coral
Coral is an organic gemstone which is cut from a mass of skeletons, secreted by polyps as a calcareous habitat. These corals usually grow at a depth of no more than about 50 feet (15 to 20 meters) in tropical to sub-tropical waters in a belt between 30...
Corundum
Definition The mineralogical name for Al2O3, the corundum family encompasses the gem varieties sapphire and ruby. It crystallizes in the trigonal structure and is surpassed only by diamond in hardness. Etymology Whether the word 'corundum' originates from the...
Cubic Zirconia
Round Brilliant-Cut Cubic Zirconia. Cubic zirconia is a man-made material used to imitate diamond and other gemstones, commonly referred to as CZ. Cubic Zirconia has a thermal insulating property while diamond is a very efficient thermal conductor. It is therefore...
Demantoid
Antique Demantoid and Diamond Earrings. At the end of the reign of Nicholas I, Emperor of Russia, and the beginning of the reign of Tsar Alexander II - after whom the mineral alexandrite was named - a new garnet variety was discovered in the Ural...
Diamond
Asscher-Cut Diamond Ring. Diamond is a gemstone composed of chemically pure carbon, with a cubic crystal structure and manifesting extreme hardness resulting from the incredibly strong chemical bonds between the carbon atoms. Diamonds are valued for their brilliance,...
Diopside
Grossular Diopside. Photo Courtesy of Rob Lavinsky, iRocks.com – CC-BY-SA-3.0
Druse
A surface covered with small projecting crystals, usually lining the sides of a cavity.
Emerald
5.11 Carat Vintage Emerald Ring. This illustrious and most esteemed member of the beryl family has long been regarded as one of the most precious of all gemstones, surpassed only by ruby. Cellini in the 16th century remarked that the value of a fine emerald would be...
Epidote
Epidote Crystals. Photo Courtesy of Rob Lavinsky, iRocks.com – CC-BY-SA-3.0
Feldspar
Feldspar var. Moonstone. Feldspar is a gem group that includes microcline, orthoclase, and plagioclase varieties. Each variety varies as to crystal structure, refractive index, color and other specifics. Gemstones include: amazonite, moonstone,...
Fire Agate
Fire Agate is an iridescent brown form of chalcedony.
Fool’s Gold
Fool's gold is the popular name for pyrite. Pyrite looks like gold but is hard and brittle and lacks the malleability of gold. Fool's Gold aka Pyrite.
Garnet
Astutely observed by Mab Wilson, author of Gems: Most of us, having been brainwashed by the dark and depressing parures of the turn of the century, forget the many beautiful colors garnets can have. Badly cut, a garnet can indeed be a melancholy object, lugubriously...
GGG
Gadolinium Gallium Garnet. A synthetic gemstone used as an early diamond substitute. GGG is manufactured by the Czochralski method and can be manufactured in many colors. With its specific gravity of 7.5, it is a lot denser than a diamond while being a lot softer (6.5...
Glass
Most glass is a man-made material sometimes used to simulate a gemstone. In that case, it's called paste. There are also three types of naturally occurring glass: Obsidian, Moldavite and Lybian Desert Glass. [table id=122 responsive=collapse...
Grossular
Tsavorite 1967 - Discovered in Northern Tanzania close to the Kenyan border by Campbell R. Bridges. Mining the deposit wasn't possible in Tanzania so Bridges crossed the border and found the green garnet in 1971 on Kenyan territory near the Tsavo national park. He...
Gueda
The Sri Lankan gueda sapphire is a pale, translucent and, until the discovery of heat treatments, useless variety of sapphire. Once heat treatment techniques were developed, this colorless gem could be turned into a striking blue stone....
Hardstone
Finely Carved Hardstone (Sardonyx) Cameo Brooch. Hardstone is a term used loosely to refer to any hard gem material used for carving. Hardstone is usually presented as cameos and intaglios but is also found as intricately fitted mosaic pieces. Commonly, hardstone...
Hematite
Hematite derives its name from the Greek word haema for blood. Thinly sliced hematite is a reddish color and, when rubbed against a scratch plate, hematite leaves a red streak. While popular in antiquity as a protection against bleeding during the Egyptian era...
Hiddenite
Hiddenite is the strongly pleochroic, bright green variety of spodumene. First discovered in North Caroline by W. E. Hidden in 1879. Sources...
Horn
Horn, commonly used in buckles, brooches, combs and hair ornaments was usually ox-horn, although it could be from any animal. With colors ranging from nearly colorless to deep rich browns, low density, lightweight horn can be carved and formed easily and has been...
Hornbill Ivory
In the fall of 2009 Stone Group Labs received an unusual item for identification. It turned out to be manufactured of hornbill ivory. Reported by Cara Williams: Carved Hornbill Clasp. Photo Courtesy of Cara Williams. We have examined the carvings in the...
Hornblende
Hornblende is a series of minerals, not a mineral in its own right. By composition, it is an iron-magnesium silicate that varies by inclusion of aluminum and calcium. Trace amounts of titanium, manganese, and sodium can also be present. Hornblende has a hardness of...
Hydrogrossular
A polycrystalline mineral in the garnet group that occurs in a green or pink color, sometimes intergrown with idocrase. Bright green samples are sometimes used as a jade simulant. Watermelon Hydrogrossular. [table id=132 responsive=collapse...
Idocrase
Idocrase is mineral species known as Vesuvianite and has several varieties. Sometimes erroneously referred to as "California Jade." Californite - Mottled or Veined Green to Yellowish Brown Xanthite - Transparent Yellow to Yellowish Bro [table id=134...
Imitation
An imitation is an object or gemstone which is used to mimic a more valuable object or gemstone. Many synthetic and natural minerals are used to mimic - for example - diamond. Another word for imitation is simulant. There is an essential difference between the use...
Iolite
Etymology The name, iolite, originates from the Greek word “iodes” meaning violet. It is often found under the misleading name of water sapphire. Iolite Facts The gemstone iolite is the transparent form of the metamorphic silicate mineral Cordierite. Strong trichroism...
Ivory
Historically, this organic gem material referred to as Ivory came only from elephant tusks. Since elephants have become a protected species and the sale of elephant ivory has been outlawed, most of the ivory we see being used in jewelry today comes from fossilized...
Jade
Jade is in the gemstone family that includes both Jadeite and Nephrite. The term Jade is still often interchanged with jadeite and nephrite without regard to the fact that they are different minerals with different properties. The term jade has its linguistic roots in...
Jadeite
Natural Burmese Jadeite Earrings.
Jasper
Jasper Cuff Links. Jasper is a member of the chalcedony family of gemstones. The name is of Greek derivation meaning spotted stone. Throughout history, it has been used for cylinder seals, intaglios, cameos and for amulets. Today we use jasper for ornamental objects,...
Jet
A Jet Box with a Pietra Dura Inlay. et is a type of brown coal used since the Stone Age for personal adornment. Formed from the fossilized wood of a Jurassic period tree that upon dying, often ended up as driftwood that was swept out to sea. From...
Kashmir Sapphire
Kashmir Sapphire and Diamond Ring. Undoubtedly, the rarest and most beautiful of all sapphires are the legendary Kashmir. As befitting such otherworldly gems, Kashmir Sapphires originate in a dauntingly remote and ruggedly beautiful corner of the northwestern...
Kunzite
Kunzite and Diamond Ring. Kunzite, a variety of spodumene, was named for George F. Kunz who was the first to describe this gem in 1902. Gem kunzite is a rose-violet color with strong pleochroism. It is vital that the rough be cut with the correct crystal orientation...
Kyanite
Labradorite
Labradorite is a mineral species of the plagioclase series of the feldspar group.
Lapis Lazuli
Lapis lazuli is a rock aggregate made up from - predominantly - the minerals lazurite, sodalite, nosalite and hauyne. It has a typical cobalt blue color, often with patches of pyrite (golden) and/ or calcite (white). It was this rock which was powdered to create the...
Malachite
Malachite is green stone with irregular bands of lighter and darker green. The name malachite comes from the Greek word malache which means mallow, for the mallow leaf of the same hue. Malachite was popular with ancient civilizations in Egypt, Rome, and Greece where...
Mallorca Pearls
Majorica is a brand name of a high-quality pearl simulants produced on the Spanish island of Majorica at the Majorica S.A. company founded by Eduardo Hugo Heusch in 1890. Created with a core of glass coated with a paste of oil and fish scales (aka essence d'orient),...
Marcasite
Marcasite is an iron sulfide mineral with an orthorhombic crystal structure. It is very brittle and unsuitable for jewelry. What we call "marcasite" in jewelry is actually pyrite - "fools gold" - that has been faceted to imitate diamonds. Popular from around 1700...
Mexican Fire Opal
Fire opal refers to the variety of transparent red, orange or orangy-red opal usually lacking play-of-color. Fire opal is cut en cabochon as well as faceted. The source for this gem material is Mexico, hence the name. Edwardian Faceted Fire Opal Brooch.Photo courtesy...
Microcline
Amazonite in Albite Specimen. Photo: Rob Lavinsky, iRocks.com Microcline is a mineral series in the feldspar group. Amazonite is a light green to greenish blue variety of Microcline. Sometimes falsely referred to as Colorado jade or Pike's Peak jade, it often has...
Moldavite
Moldavite is formed from melted rock resulting from a meteorite strike. The surface of these small specimens can be rippled (roiled), wavy, pitted and generally not smooth. Not usually seen in jewelry, but its popularity is on the rise. Moldavite from Besednice,...
Montana Sapphire
Tiffany Iris Corsage Brooch Set With Montanna Sapphires. © The Walters Art Museum. While most are familiar with the exotic beauty and rarity of Kashmir and Ceylon sapphires, the state of Montana is home to some of the most beautiful sapphires in the world. The most...
Moonstone
Moonstone is a variety of Orthoclase Feldspar. Named for its blue-white sheen's resemblance to the moon. Edwardian Moonstone Ring.
Moss Agate
Early 20th Century Moss Agate Match Safe. Moss agate is a translucent chalcedony with green moss-like inclusions, usually hornblende. When the hornblende oxidizes, the color of the moss agate can be brownish or reddish. Moss agate is often cut in smooth slabs or flat...
Mother-of-Pearl
Mother-of-pearl a nacreous, lustrous, iridescent lining of the shell of a mollusk that can be carved and cut for jewelry and other decorative purposes. It is composed of calcium carbonate bound by conchiolin which together forms nacre. Mother-of-pearl is carved into...
Nephrite
Nephrite A Jade Bi with Two Dragons, Eastern Zhou Dynasty. The term "jade" is currently used to refer to both the jadeite and nephrite varieties. This was not always the case. Ancient “jade,” revered throughout Chinese history, and the beautifully carved ancient...
Obsidian
Obsidian. Obsidian is a naturally occurring glass of volcanic origin, having an amorphous structure due to rapid cooling. It can be gray to black and often displays splotchy white patches or "snowflakes". Obsidian can also be brown to orange or red and have bands or a...
Oligoclase
Oligoclase is a mineral species of the plagioclase series of the feldspar group.
Onyx
Onyx is the name for the black and white banded variety of chalcedony. It has been used since antiquity when it was highly prized as a cameo stone. The layered color structure allows the engraver to cut the subject in one color while creating a background of another....
Opal
Opal is one of nature's most stunning contributions to the world of gemstones. A unique composition of microscopic cristobalite spheres arranged in layers within an amorphous hydrous silica jelly comprises opal's unique crystal habit. Light refracted by these spheres,...
Opaline Glass
Opaline glass was a gem imitation with a milky white to blue appearance generally cut en cabochon a popular daytime "gem" in the Georgian era. Foilbacked with metallic colored foils helped give the glass a pinkish cast.
Orthoclase
Orthoclase is a mineral series in the feldspar group. Moonstone Sources Gem Reference Guide, Los Angeles: Gemological Institute of America,...
Paraíba
Paraiba Tourmaline and Diamond Ring and Earrings.Photo Courtesy of Christie's. Paraiba is a tourmaline variety noted for its neon blue and green colors. It was discovered in 1989 in the Paraiba state of Brazil, but stones are also found in the neighboring state Rio...
Pearl
There were formerly two pearls, the largest that had been ever seen in the whole world: Cleopatra, the last of the queens of Egypt, was in possession of them both, they having come to her by descent from the kings of the East. The Girl with...
Peridot
Antique Rose-Cut Diamond and Peridot Pendant/Brooch. The golden green gemstone peridot is the gem variety of the mineral forsterite. Long valued for its exceptional color, peridot has been used in jewelry since antiquity. From the mid 1800s, peridot was a favored...
Petrified Wood
Petrified Wood is is wood that has been replaced by chalcedony aka silicified wood. In looks, it is very similar to patterned agate. Petrified Tree in Petrified Forest National Park, USA. Image by Daniel Schwen, Sept 4th, 2004.
Plastic
Plastics are man-made substances used in jewelry to imitate natural gem materials. Early plastics were organically derived, like the combination of casein and lye. With Charles Goodyear's development of the vulcanization of natural rubber, we...
Prase
A leek green colored cryptocrystalline quartz aggregate with actinolite inclusions. Usually darker and less saturated than chrysoprase. In Greek the word Prason means leek, hence the name. Dyed green agate is sometimes misrepresented as prase. Sources Gem Reference...
Prasiolite
Prasiolite is the green variety of Quartz. The material is extremely rare in nature and is only found in a handful of deposits. The gem gets its name from the Greek prason meaning "leek" and lithos meaning "stone." Most Prasiolite on the market has been created...
Pyrite
Pyrite is an opaque yellow mineral with a metallic luster. Its cubic crystal system is evident in its outward appearance and specimens are often cube-shaped. Pyrite. [table id=177 responsive=collapse...
Pyrope
Bohemian Garnet Earrings. The Czech Republic; for over 600 years the so-called 'Bohemian Garnets' have formed the bulk of pyropes used in jewellery. Especially in Victorian times, these garnets were coveted and often covered entire jewelry items. These stones were...
Quahog
A quahog is a bivalve clam native to the eastern seaboard of the United States. Used mostly as a food source, these clams occasionally produce a pearl-like gem in a beautiful natural purple color. Used as "wampum" by Native Americans in that region, they are still...
Quartz
Quartz is one of the most abundant minerals on earth and has been used as a gemstone for as long as mankind can remember. It occurs in many forms and colors but is colorless when pure which makes it an allochromatic gemstone. In order to shed some light on the...
Rhinestone
Rhinestone is the name given to rock crystal which is faceted to imitate diamond. It is also a name for colorless paste.
Rhodochrosite
Rhodochrosite is a manganese carbonate mineral with a transparent to translucent rose-pink color with undulating bands of white, gray or brown. The name derives from the Greek rhodon, meaning rose, and lithos, meaning stone. Most often it is cut en cabochon although...
Rhodonite
Rhodonite is a translucent to opaque pink to reddish color gemstone with patches or veins of black throughout. Usually cut en cabochon or drilled for beads. The name is derived from the Greek rhodon meaning rose. Gemological Information For Rhodonite Color:...
Rock Crystal
Natural Color-Change Sapphire, Rock Crystal and Diamond Pendant. The Greek word krystallos meaning "ice", provides the basis for the origin of the name Rock Crystal. This transparent colorless form of quartz conjures up the imagery of frozen rock and was so dubbed in...
Rose Quartz
Rose quartz gets its name from its rosy pink color. Because of its massive turbid crackled nature rose quartz is often carved or typically cut en cabochon or as beads. Only very large, clear pieces can be faceted. Rose quartz can be subject to fading. Rose Quartz...
Ruby
The name 'ruby' is used for red corundum which is colored by chromium. Etymology Ruby comes from the latin word for red: 'ruber'. The medieval Latin adjective 'rubinus' was derived from 'ruber' and eventually started to be used as a noun for red corundum....
Sapphire
Definition Sapphire is the term used for all colors of the gem quality mineral corundum, with red as the only exception (the red variety of corundum is called ruby.) The term sapphire, without color prefix, refers solely to blue stones. Until recently, other fancy...
Sard
Sard is a translucent to semi-transparent variety of chalcedony. The colors are similar to carnelian but they are darker and less saturated in red-brown to brown or dark orange. Carved Sard Indian Chief Pendant. Sources Gem Reference Guide, Los Angeles: Gemological...
Sardonyx
Sardonyx is a brown and white banded variety of onyx primarily used in glyptography. Antique Victorian Sardonyx Seal Fob. SourcesGem Reference...
Saussurite
Saussurite is a rock formed from green zoisite in combination with epidote, white feldspar and other minerals
Seed Pearl
Seed pearls are very small; less than a one-quarter grain in weight, smaller than 2mm in size and off-round in shape. Historically they occurred naturally and were used as a decorative border, as tiny accents in small patterns, or in larger clusters woven together to...
Serpentine
Serpentine is not a single crystal gem, but a rock-forming mineral group. The name may derive from the Latin serpentinus due to its scaly appearance and green color. Serpentine is often carved as objets d'art or made into beads. It has been used to imitate nephrite....
Shale
A fissile (easy to split) sedimentary silicate-rich rock with particles mostly in the silt and clay size. The color is usually a tone of gray but can be brown, red or green to black. Shale was used from Neolithic times for tools, ornaments, and other purposes....
Shell
Shell is the organically formed hard outer part of a saltwater or freshwater animal. Shells of all types have been used in jewelry since we first began to adorn ourselves, early beads and pendants were simply shells with a hole in them. While whole shells have always...
Smoky Quartz
Smoky Quartz is a brownish black to greyish color variety of quartz. Cairngorm is the Scottish term for smoky quartz Sources Gem Reference...
Spessartine/Spessartite
Cut Spessartite from Loliondo, Tanzania.Image by Tim Spauwen Spessartine was first discovered in the Spessart Mountains of Germany from which...
Spinel
Spinel is a mineral group which produces some of the finest gemstones, yet it has never been accepted by the general public as a valuable adornment due to poor marketing. It has a hardness that is equal to topaz and is very durable. Historically all red gemstones were...
Spodumene
The name spodumene derives from the Greek meaning burnt to ashes describing the non-gem colorless or gray variety of spodumene. There are two varieties of spodumene considered "gem quality"; hiddenite and kunzite. Colossal Mid-Century Kunzite Ring [table id=198...
Synthetic Corundum
More InformationGems & Gemology: The Quarterly Journal of the Gemological Institute of America. G&G Article Index: Synthetic CorundumFall 1939, Lined Foil Back on Corundum Produces Asterism, p. 36,...
Tanzanite
Tanzanite and Diamond Ballerina Ring. Tanzanite is a purplish blue variety of zoisite. Discovered in 1967 in Tanzania, it was introduced to the jewelry world in 1968 as Tanzanite by Tiffany & Co. ...
Thulite
SourcesGem Reference Guide, Los Angeles: Gemological Institute of America, 1988. Pp. 262-264.Schumann, Walter. Gemstones of the World, New...
Tiger’s-Eye
Tiger's-eye is chatoyant quartz. It ranges in color from brownish yellow to brown or reddish brown with iron oxide being the coloring agent. The gemstones fibrous structure causes it to be chatoyant. The chatoyancy appears because wavy lines of very fine crocidolite...
Topaz
Topaz is a gemstone which, throughout history, has shared its name with all other yellow gemstones. It was not until the mid 18th century that the name was assigned to the aluminum fluor-silicate that is uniquely topaz. During the 16th century, Cellini described a...
Tortoise Shell
Tortoise Shell Locket and Chain. Tortoise shell is the name for the outer blades covering the upper shell of the Hawksbill turtle and the Loggerhead turtle. Tortoise shell has been valued for use in jewelry since Roman times. Combs, bracelets, earrings, cameos and...
Tourmaline
Tourmaline is a large family of minerals composed of a complex boro-silicate. The most common species of the tourmaline group is Elbaite (named after the island of Elba in the Mediterranean) and it occurs in all colors of the rainbow. It was first brought to Europe by...
Trapiche
A trapiche emerald is one with a central green area radiating six green arms giving the gem a flower-like appearance. These intense green areas are outlined by dark or black albite or carbonaceous inclusions. Trapiche Emeralds.
Turquoise
Art Nouveau Turquoise Necklace. Turquoise is a blue, blue-green or grey-green opaque gemstone whose name is derived from the Turkish trade route along which these stones traveled to reach Europe in ancient times. It is almost always cut en cabochon, although sometimes...
Unakite
Vauxhall Glass
Through the eighteenth century and on into the middle of the nineteenth, Vauxhall glass was a popular gem substitute. Intense hues of highly reflective purple, orange, red, green and blue were set into butterfly, snowflake and flower motifs...
Verneuil
Auguste Victor Louis Verneuil (1856-1913) Auguste Victor Louis Verneuil is the father of gemstone synthesis. Born a watchmaker's son, Verneuil became a chemist's laboratory assistant at age seventeen and continued on to earn a PhD in chemistry, eventually becoming a...
YAG
Zircon
Zircon, While Highly Dispersive, has a Subadamantine Luster.
Zoisite
Zoisite is named for the famed collector Sigmund Zois. Discovered in Austria in 1805 in the Sau-Alp mountains, zoisite was not always considered gem material. A green specimen with hornblende inclusions and, more importantly, large opaque ruby inclusions, was...