About Jewelry

• Agat
• Amethyst
• Azurite
• Alexandrite
• Banded Agate
• Black Opal
• Black Pearl
• Coral
• Diamond
• Gold
• White gold
• Yellow gold
• Fold over clasp
• Karat

• Lobster claw clasp
• Marcasite
• Malachite
• Moonstone
• Opal
• Pearl
• Peridot
• Platinum
• Quartz
• Red diamond
• Ruby
• Sapphire
• Sardonyx
• Seftonite

• Silver
• Silver 800
• Sterling Silver
• Sodalite
• Sugilite
• Tanzanite
• Tiger's eye
• Topaz
• Tourmalinated quartz
• Troy weight
• Water sapphire
• Zircon

AGATE
Agate is a variety of chalcedony (a family of microcrystalline quartz). Agate is a very common stone that is often used in jewelry. It is found in a wide range of colors, including black, gray, brown, reddish, green, pink, blue, and yellow. Agate can be flecked with color and is often banded, exhibiting layers of quartz. Agate is porous and takes dye easily; it is frequently dyed to enhance the coloration and the banding. White agate was used often in Victorian jewelry, mostly as a background. Moss agate has green, red or black dendritic inclusions. Onyx is agate whose bands are parallel. Eye agate has banding arranged in concentric circles. Agate has a hardness of 6.5 to 7 and a specific gravity of 2.6. The agate pin above is from Miracle.

AMETHYST
Amethyst (Greek for "not drunken") is a form of the mineral quartz, and is a relatively common gemstone. Amethyst is usually purple, but can range in color from pale lavender to a very deep, reddish purple to a milky color to green. Deeper-colored amethysts are more highly valued. The ancient Greeks believed that amethyst made one immune to the effects of alcohol. Synthetic amethysts are hard to distinguish from the real stone.

AZURITE
Azurite is a beautiful copper-based blue mineral that is often used in jewelry. The color ranges from very deep blue to pale blue. Azurite has also been used as a dye for paints and luxury fabrics. Azurite is hydrated copper carbonate; its chemical formula is Cu₃(CO₃)₂(OH)₂. Malachite (another copper-based mineral) and azurite are often found together. Azurite has a hardness of 3.5 to 4 (relatively soft) and a specific gravity of 3.7 to 3.9. Azurite is found in massive monoclinic crystals in Australia the southwestern USA, France, Mexico, Morocco, Nambia, Zaire, and Europe. Azurite is sometimes coated with a colorless wax or impregnated with plastic in order to enhance the color and increase the hardness.

ALEXANDRITE
Alexandrite is a mineral (a type of chrysoberyl) that appears to be different colors depending on whether it is viewed in natural or artificial light. Alexandrite appears to be red when seen in candle light and blue to green when seen in fluorescent light. Alexandrite was discovered on the birthday of the Russian Czar Alexander II, and it was named in his honor. Alexandrite is mined in Russia, Brazil, Burma, Ceylon, and Rhodesia. Laboratory-produced alexandrite is common, and it is often sold as natural alexandrite. Alexandrite has a hardnessof 8.5 and a specific gravity of 3.64-3.74.

BANDED AGATE
Banded agate is a type of agate with distinct layers of color.

BLACK OPAL
Black opals are a valuable type of precious opals with a dark ground color. They are luminous, iridescent, and frequently have inclusions of many colors (" fire"). Opal is a mineral composed of silica (and some water) and is a species of quartz. The rainbow-like iridescence is caused by tiny crystals of cristobalite. Many opals have a high water content - they can dry out and crack if they are not cared for well (opals should be stored in damp cotton wool). Opals have a hardnessof 5.5 to 6.5 and a specific gravity of 1.98-2.50. Black opals are found in Australia.

BLACK PEARL
Black pearls (also called Tahitian pearls) are dark-colored pearls. They are produced by the large, black-lipped pearl oyster Pinctada margaritifera (also called the Tahitian black pearl oyster), a mollusk found in the tropical Indo-Pacific Ocean. Black pearls come in many colors, including many body shades and overtone tints including gray (light gray to almost black), peacock green (especially valuable), aubergine (eggplant), and deep brown. The color of the dark nacre is determined by the minerals in the oyster's diet (plankton) and in its environment. Many "black pearls" are dyed or irridiated to enhance or change their color; it is difficult to tell a natural pearl from a treated pearl. Tahitian pearls are graded on six factors: 1.Shape (round is most valued), 2.Size (the larger the better), 3.Surface Quality= (clean is superior to blemished), 4.Luster (the more high-gloss luster the better), 5.Nacre Thickness (thicker is better and longer lasting), and 6.Color (overtones atop the body color add value to the pearl. The most sought-after color is peacock green and darker colors are more valuable Overtone colors include blue, pink, gold, silver, aubergine, and peacock green).

CORAL
Coral is an animal that grows in colonies in the ocean. Coral polyps secrete a strong calcium structure that is used in jewelry making. Coral ranges in color from pale pink (called angelskin coral) to orange to red to white to black. The most valued colors are deep red (called noble coral) and pink. In jewelry making, coral is either carved into beads, cameos, or other forms, or is left in its natural branch-like form and just polished. It used to be thought that coral protected the wearer, so it was a traditional gift to children. Coral has a hardness of about 3.5 and a specific gravity of 2.6 to 2.7. Since it is composed of calcium carbonate, coral will effervesce if touched with acid. Imitation coral is made from glass, porcelain, or plastic.

DIAMOND
Diamonds are precious, lustrous gemstones made of highly-compressed carbon. Diamonds are one of the hardest materials known. Diamonds have a hardness of 10, a specific gravity of 3.5, and a refractive index of 2.417 - 2.419. Colors of diamonds range from colorless, yellow, orange, brown, to almost black. Rarer colors are red, blue, green, and purple; these colors (called fancies) are quite valuable. Canary diamonds have a deep yellow color. A diamond's value is based on the "4 C's": color, cut, clarity, and carat weight. A diamond's color (saturation) is rated on an alphabetical scale ranging from D (white) to Y (yellow). "Z" diamonds are fancy, or deep-colored diamond. A diamond's cut is designed to maximize the stone's natural "fire"; brilliant cuts are preferred. A diamond's clarity depends on the number and size of its flaws and inclusions (of other minerals, like quartz). Clarity is rated from FI (flawless), IF (flawless at 10x magnification), a series of V ratings (very small flaws at 10x magnification), a series of S ratings (small flaws at 10x magnification), to I1, I2, and I3 (having inclusions visible to the naked eye). A diamond's carat weight is simple how much it weighs (a carat is about 0.2 grams or about 0.007 ounces). The largest-known gem-quality diamonds include the Cullinan (aka the Star of Africa, 530.20 carats), the Excelsior, the Great Mogul (an ancient Indian diamond which is said to have originally weighed 787.5 carats, but its location is not not known and nothing about it has been authenticaed), the Darya-i-Nur, the Koh-i-Nur, and the Hope diamond (named for a purchaser, Henry Thomas Hope).

YELLOW GOLD
Yellow gold is gold that has been alloyed with a mix of 50% copper and 50% silver.

KARAT
Karat (abbreviated Kt) is a measure of the fineness of gold. 24 karat gold is pure gold. 18 karat gold is 18/24 gold (about 75% gold - three quarters gold). 14 karat gold is 14/24 gold (about 58% gold - a little over half gold). 12 karat gold is exactly half gold. 10 karat gold is 10/24 gold (only about 43.5% gold - less than half gold).

LOBSTER CLAW CLASP
A lobster claw clasp is a jewelry fastener that resembles the claw of a lobster. A tiny spring keeps the arm of this clasp closed. It is used to attach two other rings or links of a necklace or bracelet.

  MARCASITE
Marcasite is a shiny, metallic semi-precious stone. It is actually iron pyrite. Marcasite is generally faceted. The Czech guilloche pin above is studded with marcasites.

  MALACHITE
Malachite is an opaque semi-precious stone with layers of deep green and light green. It is usually found in copper mines; malachite is about 57% copper. Malachite was used as jewelry thousands of years ago by the ancients Egyptians. Malachite is usually cabochon set in silver. Russian malachite carvings were done in miniature and in large scale; malachite was also inlaid in furniture. Malachite has a hardness of 4 and a specific gravity of 3.80. It is monoclinic; it has one two-fold axis of symmetry. Malachite is sometimes coated with colorless wax, oil, or hardening agents to increase its durability and enhance its appearance.

  MOONSTONE
Moonstone (orthoclase) is a semi-translucent stone that is made of albite and orthoclase feldspar. It is usually whitish-blue, but can be colorless, yellow, orange, gray, or even reddish. Moonstone is usually set as a cabochon. Moonstone was very popular early in the 20th century and was extensively used in Art Nouveau jewelry. Moonstone has a hardnessof 6 and a specific gravity of 2.57. It is monoclinic; it has one two-fold axis of symmetry. Adularia is a common type of moonstone. Oligoclase is another type of moonstone; Labradorite and albite are rare forms.

  OPAL
Opals are semi-precious stones that are luminous and iridescent, frequently with inclusions of many colors (" fire"). Opal is a mineral composed of noncrystalline (amorphous) silica (and some water) and is a species of quartz. There are three major types of opals: common opal, opalescent precious opal (white or black, with a rainbow-like iridescence caused by tiny crystals of cristobalite), and fire opal (a milky stone that is fiery orange to red in color with no opalescence). Contra luz opals are transparent opals that show a brilliant play of iridescence only when light shines through the stone. Many opals have a high water content - they can dry out and crack if they are not cared for well (opals should be stored in damp cotton wool). Some opals are treated with oil, wax or resin to enhance their finish. Opals have a hardnessof 5.5 to 6.5 and a specific gravity of 1.98-2.50. Opals are found in many places worldwide, including Kenya, Czechoslovakia, Brazil, Peru, Honduras, Mexico, Canada, and the USA -- but Australia has a tremendous variety of beautiful opals.

  PEARL
Pearls are organic gems grown within oysters and a few other mollusks. Pearls are formed when a foreign object (like a tiny stone) has made its way into the mollusk's shell. The mollusk secretes nacre, a lustrous substance that coats the intruding object. As thousands of layers of nacre coat the intruder, a pearl is formed; this process takes up to seven or eight years (an oyster's useful life span). The most valuable pearls are perfectly symmetrical, large, naturally produced, and have a shimmering iridescence (called orient luster). There are many types of pearls, including natural pearls (made with no human interference), cultured pearls (pearls made by inserting a bit of a mother-of-pearl) into [nucleating] a living oyster or by inserting a bit of foreign tissue), baroque pearls (irregularly-shaped pearls), freshwater pearls seed pearls (tiny pearls), Biwa pearls (a type of freshwater pearl from Lake Biwa, Japan from the freshwater mussel, Hyriopsis schlegeli), blister pearls (grown attached to the shell), black pearls (gray to black pearls), Mabe pearls (cultivated blister pearls), etc. Pearls can be gently cleaned with mild soap and water. The biggest natural pearl, known as the "Pearl of Allah" or "Pearl of Lao-tse," weighs 14 pounds (6.4 kg).

  PERIDOT
Peridot (also known as the "evening emerald" and chrysolite) is a yellow-green semi-precious stone with an oily luster; peridot is a transparent, green form of olivine. Peridot exhibits double refraction; when you look through the stone, things appear double. For example, when looking into a faceted peridot gemstone, the number of bottom facets appears to be double the actual number of facets. Most peridots are from a volcanic island in the Red Sea, Zebergit/St. John, the "Serpent Isle." Peridots have been found in meteorites. Peridot has a hardness of 6.5. Peridot cat's eye also exists.

PLATINUM
Platinum is a very strong, dense precious metal with a white color. Platinum jewelry is usually 90%-95% pure, is very sturdy, and holds stones well; to strengthen the metal and increases the workability of the platinum, platinum is usually alloyed with 5 to 10 percent of another platinum group metal (like ruthenium, palladium, or iridium) and/or cobalt. Platinum is 60% heavier than gold Platinum was only discovered in the 1700's in Russia. Platinum is abbreviated Pt. and Plat.

QUARTZ
Quartz is a crystalline mineral that come in many forms, including amethyst aventurine, citrin, opal rock crystal, tiger's eye, rose quartz,and many others. Rutilated quartz and tourmalinated quartz have needle-like inclusions of other minerals. Quartz has a hardness of 7.0. This common mineral is found worldwide.

  RED DIAMOND
Red diamonds are rare, fancy diamonds and are quite valuable. Diamonds are precious, lustrous gemstones made of highly-compressed carbon; they are one of the hardest materials known. Diamonds have a hardness of 10, a specific gravity of 3.5, and a refractive index of 2.417 - 2.419.

  RUBY
Rubies are precious stones and a member of the corundum family (Al2O3). Rubies range in color from the classic deep red to pink to purple to brown. Rubies are extremely hard; only diamonds are harder. During the renaissance, people thought that rubies could counteract poison. Laboratory-produced rubies were created in the 1890's; they are difficult to distinguish from natural rubies. The biggest ruby in the word is the Raviratna, which weighs 3,600 carats. Rubies have a hardness of 9 and a specific gravity of 3.9 - 4.1. Rubies are found in Afghanistan, Australia, Brazil, Cambodia, India, Myanmar (Burma), Malagasy Republic, Malawi, Pakistan, Sri Lanka (Ceylon), Tanzania, Thailand, United States, and Zimbabwe (Rhodesia).

  SARDONYX
Sardonyx is a semi-precious stone that is formed by two layers, a red-brown layer of sard and a gray, white, black or brown layer of onyx. Sardonyx is a type of quartz. Sardonyx is frequently carved to make intricate cameos and seals.

  SEFTONITE
Seftonite is a translucent, moss green type of chalcedony. It is found in South Africa and North America

SILVER 800
Silver 800 is silver with a fineness of 800, that is, it contains 800 parts per thousand (or 80 percent) silver and 200 parts per thousand (or 20 percent) copper. Silver 800 is used for casting.

STERLING SILVER
Sterling is silver with a fineness of 925, that is, sterling is 925 parts per thousand (or 92.5%) silver and 75 parts per thousand (or 7.5%) copper (the copper increases the silver's hardness). Sterling is quite malleable. The pin pictured above is a rhinestone-studded sterling bow made by Trifari.

  SODALITE
Sodalite is a dark blue mineral with streaks of white, gray, pink, or green. It is used for carvings and jewelry. Sodalite is one of the mineral components of lapis lazuli. Sodalite is sodium aluminum silicate chloride; its formula is Na4Al3(SiO4)3Cl. Sodalite has a hardness of 5.5 to 6 and a specific gravity of 2.1 - 2.3. Sodalite is found in Brazil, Canada, India, Italy, Namibia, United States, and Russia.

  SUGILITE
Sugilite is a medium to dark purple semi-precious gemstone (it can also range from pink to brown to black). It is usually opaque with a waxy luster (but can be translucent) and often has brown, pink and white inclusions, looking like a purple version of turquoise. It is usually polished and not faceted. Sugilite has a hardnessof 5.5-6.5 and a specific gravity> of 2.75 - 2.80. This stone is not enhanced - massive stones are often found. Sugilite is Potassium Sodium Lithium Iron Manganese Aluminum Silicate; its formula is KNa2Li3(Fe, Mn, Al)2Si12O30. This stone was named for Ken-ichi Sugi, the Japanese geologist who discovered it in 1944. It is found in Iwagi Island, Shikoku, Japan and Mont Saint-Hilaire, Quebec, Canada, but the largest deposits are in northern South Africa.

   TANZANITE
Tanzanite (strontium-rich Calcium-aluminum silicate) is a valuable, transparent, blue-violet type of zoisite resembling sapphire. Tanzanite has a hardness of 6 and a specific gravity of 3.35. It is often heat-treated in order to produce a deeper blue-violet color. This mineral was discovered in 1967 by Manuel d'Souza (an Indian tailor) southwest of Mt. Kilimanjaro in Tanzania, Africa. Tanzanite is one of December's birthstones.

  TIGER'S EYE
Tiger's eye is a yellowish-brown to reddish-brown gemstone that has a silky luster. This gemstone has bands of yellow and brown; when viewed from the opposite direction, the colors are reversed. Tiger's eye is usually highly polished and set as a cabochon(or cut as a bead) to display the stone's chatoyancy (light reflected in thin bands within the stone). Tiger's eye is a type of chatoyant quartz with fibrous inclusions (especially crocidolite). This stone is sometimes heat-treated. Tiger's eye has a hardness of 7.0. Most tiger's eye is mined in South Africa, but it is also found in Australia, Brazil, Burma (Myanmar), India, Namibia, Sri Lanka (Ceylon), and the USA. Green-grey varieties of this stones are called cat's-eye quartz. Blue-grey to bluish varieties are called hawk's-eye. Deep brown varieties of this stone are called bull's-eye or ox-eye.

  TOPAZ
Topaz (aluminum silicate fluoride hydroxide) is a very hard gemstone that ranges in color from brown, to yellow to blue to pink. Pink topaz is usually created by irradiating common yellow topaz. Other colors are often created by heat-treating and/or irradiating topaz. Imperial topaz is golden orange-yellow topaz; it is the most valuable topaz Topaz has a hardness of 8 and a specific gravity of 3.5-3.6. Topaz may have been named for the legendary Topasos Island in the Red Sea.

TOURMALINATED QUARTZ
Tourmalinated quartz is a variety of transparent quartz that has needle-like inclusions of black to dark green tourmaline crystals. This beautiful stone is found worldwide. Tourmalinated quartz has a hardness of 7.0. This stone is not enhanced.

TROY WEIGHT
Precious metals (like gold, platinum, and silver) are measured in troy weight, which has units of pennyweights, ounces, and pounds. Troy ounces and pounds are different from everyday US measures.

"WATER SAPPHIRE"
"Water sapphire" is not a true sapphire, but is iolite, a more common, softer, and much less expensive mineral. It is a transparent, violet-blue, light blue, or yellow-gray mineral. Iolite is pleochroic; a single stone will show many colors (in the case of Iolite, violet-blue, light blue, and yellow-gray). Iolite has a hardness of 7 - 7.5. Iolite is found in Sri Lanka, India, Madagascar and Burma.

  ZIRCON
Zircon (zircon silicate) is a lustrous gemstone that comes in colors ranging from golden brown to red to violet to blue. Pure zircon is colorless, but most zircon stones are brown. Zircon stones can be heat-treated to become blue or colorless; sometimes, heat-treated stones revert to their original color. Clear zircon is sometimes sold (intentionally or otherwise) as diamond. It has a hardness of 7.5 and a specific gravity of 3.90-4.71.

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