Gemstones

The following information comes from the book, "Rock and Gem" The Difinitive Guide to Rocks, Minerals, Gems and Fossils put out by the Smithsonian Project Coordinators.
Kincaidesigns doesn't use precious stones in the handmade jewelry, only those of semi-precious nature. While there are more gemstones than listed below (alphabetically), the noted gemstones are those found in the birthstone chart above. For a great source of information, history and meanings of gemstone, I would suggest the book sourced from this information.

What is a Gemstone?
The term "Gemstone" can be used to identify any mineral highly prized for it's beauty, durability, and rarity. A Gem is a mineral enhanced in some manner by altering the shape, usually by cutting or polishing. Over 4000 minerals have been identified, however, fewer than 100 are classified as gemstones.

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What classifies a Gemstone as Precious or Semi-Precious?
Only a minority of these 100 minerals classified as Gemstones are of major importance. Some of these are the diamond, corundum (sapphire and ruby), beryl (emerald and aquamarine), chrysoberyl, feldspar (sunstone, moonstone, and labradorite), garnets, jadeite and nephrite (jade), lazurite (lapis lazuli), olivines (peridot), opal, aragonite (pearl), quartz (in all its varieties), spinel, topaz, tourmaline, turquoise and zircon. These are usally divided into two categories: precious and semiprecious. Diamond, the two color varieties of corundum, sapphire, ruby and the deep variety of beryl (emerald) are considered precious. You can find some semiprecious stone in the unique handmade jewelry here at Kincaidesigns. Some of these semiprecious stones used in the handmade jewelry are peridot, amethyst, onyx, garnet, aquamarine, quartz, lemon quartz, tourmaline, and more.

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Agate The semiprecious type of chalcedony is a variety of quartz (which means it has the same physical properties as those in quartz). Most agates form in cavities in ancient lavas or other extrusive igneous rocks. For the most part, agates are categorized by the colored bands in a concentric form. These lines usually follow the outline in which the mineral was formed. The band of colors are determined by differing impurities present and occur in shades of white, yellow, gray, pale blue, brown, red or black.

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Alexandrite Alexandrite is the gemstone variety of chrysoberyl. It is one of the rarest and most expensive gems. A beryllium aluminum oxide, chrysoberyl is hard and durable, inferior in hardness only to corundum and diamond. Alexandrite appears green in daylight but red under tungsten light. The original deposit of alexandrite in the Urals of Russia is mainly worked out, but some is still mined in Brazil and Sri Lanka.

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Amethyst Amethyst is a variety of vitreous quartz with purple, violet or red-purple coloration. The name, was derived for the ancient Greek word "amethustos" which literally means "not drunk". It was believed to guard against drunkenness. Amethyst has also been favored by royalty because of it's purple "regal" hue. Amethyst is usually found in most countries where granitic rocks are exposed and the coloration is due to traced of iron.

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Aquamarine Few people have ever heard of the mineral beryls, but almost everyone has heard of it's principle gemstones, Emeralds and Aquamarine. Aquamarine means "sea water" and is almost always found in cavities in pegmatites or alluvial deposits. It forms much larger and clearer crystals than emerald. In ancient times, aquamarine amulets engraved with Poseidon were thought to protect sailors.

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Bloodstone Bloodstone is a dark green variety of chalcedony colored by traces of iron silicates and with patches of bright red jasper throughout its mass. It's also known as heliotrope which is derived from the Greek "helio", meaning "sun", and trepein", meaning "turning." Both polished and unpolished stones show red spots on a dark green backgound resembling blood, hence the name, bloodstone.

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Citrine and Yellow Citrine Citrine is yellowish to brownish quartz and resembles yellow topaz. It is colored by hydrous oxide, and is found in the same hexagonal crystals as the other varieties of crystalline quartz. Natural citrine is much less common than amethyst or smokey quartz, both of which can be heat-treated to turn their color into that of citrine. Most citrine that is available today is the heat-treated amethyst. Gem-quality citrine is found on the Isle of Arran, Scotland; in the Ural Mountains of Russia; near Hyderabad, India; in Dauphine, France; in Minas Gerais, Brazil; in the Salamanca Province of Spain; and in North Carolina.

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Diamond The Diamond is the hardest mineral on earth and is made up of pure carbon. Most diamonds come from two rare kinds of volcanic rocks, lamproite and kimberlite, but they are much older than the rocks in which they are found. The right conditions for diamonds to crystallize occur in the mantle of the Earth, more than 95 miles deep. Kimberlite magmas originate particularly deep and when they erupt, diamonds are forced to the Earth's surface.

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Emerald Emerald is the grass green variety of Beryl. Its name originates from the Greek word "smaragdos", which seems to have been given to a number of green stones besides emerald. Emeralds green color results from trace chromium. Trace vanadium may also be present, and beryls colored by vandium alone can be emerald-green, but there are differences in opinion as to whether or not they should be called emerald. Flawless emeralds are rare so various treatments have been devised to hide or disquise flaws. The emerald was synthesized in 1937 and synthetic emeralds are manufactured in the United States. They appear to be very natural crystals in color and beauty. The world's greatest natural collecion of natural emeralds is held in the Republic of Bogota Bank in Columbia.

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Garnet See Ruby. "Ruby" is a term applied to fine garnets as well: Cape rubies, autraliean rubies and Arizona rubies are all garnets.

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Jasper Jasper is an opaque fine grained or dense variety of cryptocrystalline quartz. Its a chalcedony incorporating various amounts of other materials that give it both its opacity and color, Red-Brick to brownish-red. Jasper has been used for jewelry and ornamentation since paleolithic times. The Babylonians believed that jasper influenced women's diseases and was a symbol of childbirth.

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Lapis Lazuli The main component in Lapis Lazuli is Lazurite and accounts for the intense blue color. Lapis Lazuli also contains the minerals pyrite and calcite and a few other minerals. The best quality lapis lazuli is an intense dark blue with minor deposits of white calcite and brassy yellow pyrite. It is extremely rare and commonly found in forms of crystalline limestone. Ancient references to "sapphire," the "sapphirus" of the Romans, usually refers to lapis lazuli. Its modern name originates in the Persian word "lazhuward," meaning "blue," and the Arabis word "lazaward," meaining "heavan" or "sky." The mines of Afganistan remain a major source.

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Moonstone Anorthoclase is one of several feldspars that show a white or silvery iridescence when cut "en cabochon". They are classified as moonstone, other moonstones are orthoclase, sanidine, albite and oligoclase. The iridescence, called "schiller", results from the minute interlayering of a different feldspar that developes by internal chemical separation during the process of crystallization.

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Onyx Onyx is the striped, semiprecious variety of agate with white and black alternating bands. It's a rare stone that can be artificially reproduced by dying pale, layered agate. The name come from the Greek "onux", meaning "nail" or "claw", referring to the mineral's color. The name onyx is properly applied to the agate variety only. Other varieties include carnelian onyx (with white and red bands), and sardonyx (with white and brown bands.) Natural onyx comes from India and South America and is commonly used for cutting cameos and intaglios because its layers show a color contrast.

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Opal Opal derives it's name from the Roman word "opalus", a Latinized version of the older Sanskrit upala, meaning "precious stone." Opal is hardened silica gel and usually contains 5-10% water in submicroscopic pores. Precious opal is the least crystalline form of the mineral, consisting of a regular arrangement of tiny, transparent, silica spheres with water in the intervening spaces. Although it is known for its ranging colors, opal is essentially colorless in it's purest form.

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Pearl Pearl is a concretion formed by a mollusk and cosisting of the same material as the mollusk's shell, which is the mineral aragonite (calcium carbonate). In addition to aragonite, the shell contains small amounts of conchiolin, a hornlike organic substance; together these are called nacre, or mother of pearl. The finest pearls are those produced by mollusks whose shells are lines with mother of pearl. These mollusks are limited to a certain species of saltwater oysters and freshwater clams. The mollusks body tissue is called the mantle, and when a foreign particle enters the mantle, the cells build up more or less concentric layers of pearl around it to protect the mantle. Irregular shaped pearls have grown in the muscular tissue and blister pearls (flat on one side) grow adjacent to the shell. Pearls are valued by their translucence, luster, surface color and shape.

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Peridot Olivine, or it's gemstone variety peridot, has been mined for over 3,500 years on the former John's Island in the Red Sea (the island is now called Zebirget.) Olivines are usually yellow-green, but can be yellow, brown or gray. Pakistan is the principal source for gem quality olivine and is generally found where there has been little opportunity for alteration, such as in dry climates or in recently formed rocks such as ultramafic lavas.

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Ruby Ruby is the red variety of the mineral corundum, an oxide of aluminum. Its color ranges from deep cochineal to pale rode-red and sometimes a hint of purple. The most valued is blood red. The name Ruby comes from the Latin "ruber" meaning "red." Many rubies are heat treated to improve their clarity and/or color. Rubies tend to be small, anything over 10 carats is unusual, so large rubies are of high value. "Ruby" is a term applied to fine garnets as well: Cape rubies, autraliean rubies and Arizona rubies are all garnets.

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Sapphire Rubies and sapphires are the same mineral, corundum, an oxide of aluminum. The name coundum is probably derived from the Sanskrit kuruvinda, meaning "ruby", the name given to red corundum. When it is found in other colors it is called "sapphire." Although popularly thought of as being blue, sapphires can be colorless, green, pink, and a wide range of other hues. Rare pink-orange stones are called padparadscha and sapphire that appears blue in natural light and reddish or violet in artificial light is called Alexandrine or Alexandrite sapphire. All colors of corundum are knows as sapphires (pink sapphire, yellow sapphire, etc ) except red, which is a ruby. Next to the diamond, corundum is the second hardest mineral on earth.

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Sardonyx Sardonyx is another form of onyx. "Sard" is a translucent, light to dark brown chalcedony. Sard takes its name from the Greek "Sardis", the capitol of ancient Lydia. It shared it's name "sardion" with carnelian until the Middle Ages. Bands of sard and white chalcedony are called sardonyx. Sard is famously found in Ratnapura, Sri Lanka. Other sources are India, Brazil, and Uruguay. Like onyx, it is also commonly used for making cameos and intaglios because of it's contrasting colored layers.

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Tanzanite The sapphire-blue variety of Zoisite, Tanzanite is the most valuable of it's kind. Other colors zoisite comes in are yellowish-green, green, white, green-brown or gray. Tanzanite is found in the veins of quartz and pegmatites. They are commonly mistaken for sapphires and they are often color treated to remove any browns to enhance its color. They may appear more violet in incandescent lights. Tanzanite comes from Tanzania and Pakistan.

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Topaz Topaz is one of the sources of the island Zebirget in the Red Sea. This island has had a few previous names, one of which was Topazios. The word Topaz is also thought to derive from "tapaz", the Sanskrit name for "fire." Many authorities believe that the stone called topaz today was unknown to the ancients and that the name topazos referred to olivine (peridot), which is known to be found on the island of Topazios (Zebirget) as well. Topaz is found in a wide range of colors, the sherry-yellow being particularly valuable and the pink topaz (natural pink topaz) being the most valuable and rare. The yellow topaz becomes pink on exposure to a moderate heat, and most pink topaz today is heat treated yellow topaz. Other colors of topaz include blue, which is sometime indistinguishable from aquamarine, brown topaz, and white (which has been mistaken for diamond.)

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Tourmaline Tourmaline is the name given to a family of borosilicate minerals of complex and variable composition, but all members have the same basic crystal structure. There are 11 species of Tourmaline group, including elbaite, dravite, schorl, and liddicoatite. Numerous varieties are also recognized, including indicolite (blue), achroite (colorless), rubellite (pink or red), and verdalite (green), and these variety names apply to more than one toumaline species. Although tourmaline is a common mineral, gem-quality tourmaline is almmost exclusively limited to pematites, which is the name given to very coarse grained, igneous rocks. These rocks are one of the sources of other importand minerals as well. Tourmaline is generally found in Sri Lanka, Canada and the US.

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Turquoise Turquoise was one of the first gemstones to be mined and some turquoise beads found in Mesopotamia, (present day Iraq), date back to around 5000 BC. It varies in color from sky-blue to green, depending on the amount of iron and copper it contains. Turquoise from several sources was first transported through Turkey, probably accounting for its name, which is French for "Turkish." Turquoise is mined in Iran, Tibet, northern Africa, Australia, Siberia, England, Belgium, France, Poland, Ethiopia, Mexico, Chile, and China.

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Zircon One of the few stones to resemble the diamond in fire and brilliancy is zircon. It's colorless stones have been intentionally and mistakenly substituted for the diamond. Zircon exhibits double refraction and bottom facets seen through the top of a cut stone will appear double, diamond doesn't share this property. Zircon is also significantly softer than diamond and cut stones will show wear on the edges of the facets. The name Zircon is from the Arabic "zargun," derived in turn from Persian zar, meaning "gold," and the Arabic "gun," meaning "color." They can be colorless, yellow, gray, green, brown, blue and red.

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