Buyers Guide - Jewelry Glossary

Jewelry Glossary of Terms

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 hardness of 8.5 and a specific gravity of 3.64-3.74.

Alloy

An alloy is a combination of two or more metals. Common alloys used in jewelry are: gold under 24 Kt (mixed with silver, copper, and/or other metals), sterling silver (92.5% silver, 7.5% copper), brass (roughly half copper, half zinc), bronze (at least 60% copper with tin and perhaps other metals), and pewter (tin, lead, antimony, and a bit of silver or copper).

Amber

Amber is translucent fossilized tree resin (from conifers), a natural hydrocarbon that comes in many colors, including yellow, reddish, whitish, black, and blue. Amber is flammable. Rubbing amber produces static electricity. The word electricity comes from the Greek word for amber, "elektron." It used to be thought that amber possessed magical powers that protected the wearer from evil. Pressed amber consists of small pieces of amber that have been fused together to form a larger piece. Fake amber is easily made from plastics, and buyers must beware of cheap imitations sold as natural amber. Amber has a hardness of 2.5 and a specific gravity of 1.05-1.10.

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.

Ametrine

Ametrine is a variety of quartz, a mixture of amethyst and citrine. Ametrine is partially purple and partially orange-yellow.

Aqua Marine

Aquamarine is a transparent, light blue or sea-green stone that is porous. Today, blue aquamarines are more highly valued, but this was not true in the past, when sea-green stones were prized. Heat-treatment turns greenish stones bluer. The best aquamarines come from Brazil. Large aquamarines are relatively common. Aquamarines are usually faceted but when they are cabochon cut, a cat's eye effect or asterism may appear. Aquamarines belong to the beryl family of stones. Aquamarine has a hardness of 7.5-8 and a specific gravity of 2.65-2.85.

Asscher Cut

Joseph Asscher was an eminent diamond cutter who cut the 3,106 carat Cullinan diamond. Asscher worked in Amsterdam. In 1902, his company, the Asscher Diamond Co., developed and patented the Asscher cut, a squarish step cut with an almost octagonal outline. This new cut enhanced the fire and light of the stone; it had a small table, a high crown, wide step facets, a deep pavilion and square culet. This cut became very popular in Art Deco jewelry and was a forerunner of the emerald cut. Recently, the Royal Asscher Diamond Co. resumed production of the original Asscher cut diamonds.

Baguette

A baguette cut is a stone (usually a diamond) that has been cut into a long, rectangular shape. Baguette means "stick" or "rod" in French.

Band	A band is a ring that is made from a thin, flat, ribbon-like strip of material (usually metal). The band can be unadorned or decorated. Wedding rings are often bands.

Baroque Pearl

Baroque pearls are irregularly-shaped pearls. Baroque pearls can be natural or artificial.

Bezel Setting

A bezel setting is a way of setting a stone in which the stone is held by a band of metal around the outside of the stone.

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 hardness of 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).

Blister Pearl

A blister pearl (also called a bouton pearl) is a pearl that developed attached to the inside of a mollusk's shell. This type of pearl must be cut off the shell, and is therefore hemispherical. Because of their shape, blister pearls are mostly used for earrings.

Blue Diamond

Blue 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.

Brilliant Cut

Brilliant cut stones have 56 facets, 32 facets are above the girdle, 24 are below. Most modern-day diamonds are brilliant cut since it maximizes the amount of reflected light from the stone (its natural fire). The brilliant cut was introduced in the 1600's.

Briolette Cut

A briolette (or drop cut) is a pear-shaped cut gemstone with triangular facets on top. This type of stone makes a nice pendant.

Brooch

A brooch (also called a pin) is an ornament that can be pinned to a garment.

Cabochon

A cabochon is a stone that has a rounded, domed surface with no facets. A cabochon garnet is also called a carbuncle.

Canary Diamond

Canary diamonds are diamonds that have a deep yellow color. 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

Chalcedony

Chalcedony is a family of minerals (microcrystalline quartz) that are often milky to gray to bluish in color. Chalcedony includes agate, carnelian (waxy red), chalcedony (blue), chrysoprase (green), onyx (black and white), bloodstone, sard (brownish-red), jasper (hornstone), seftonite, and others. Chalcedony is porous and translucent. Chalcedony has a hardness of 6.5-7 and a specific gravity of 2.6.

Channel Set

Channel set jewels rest in a metal channel, held in only by a slight rim which runs along the edges of the channel. Channel set jewels are usually round or baguette shaped.

Clarity

Clarity is the clearness of a gemstone, or the lack of internal flaws. The clarity scale for diamonds runs from FL (flawless, with neither internal nor external flaws), to I3 (having many clearly visible imperfections using only the naked eye). A ten-power loupe is used to examine a diamond for clarity.

Cluster Setting

A cluster setting is one in which small stones or pearls are set around a larger stone.

Crown

The crown is the upper part of a gemstone.

Cubic Zirconium

Cubic zirconium (also known as cubic zirconia) is an inexpensive, lab-produced gemstone that resembles a diamond. Cubic zirconia was developed in 1977.

Cuff Bracelet

A cuff bracelet is a stiff, relatively wide bracelet.

Culet

A culet is the bottom point of a gemstone or a small facet that is ground at the base of a brilliant-cut gemstone. The culet prevents splintering of the stone. Modern stones rarely have a faceted culet.

Cultured Pearls

Cultured pearls are pearls produced by oysters that have been surgically injected (nucleated) with bits of mussel shell. After 5-7 years, the oysters are retrieved and the pearls are harvested. This method of "manufacturing" pearls was invented in 1893 by Kokichi Mikimoto.

Cushion Cut

Cushion cut stones are shaped like a cushion - they have a squarish shape that is rounded on the edges. These stones usually have facets similar to those of a brilliant cut stone.

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 its purchaser, Henry Thomas Hope).

Die Stamping

Die stamping (also known as machine-stamping) is a process in which sheet metal is cut and shaped between two dies, forming a pattern in relief. Two steel dies are used, the male die has the design in cameo (protruding); the female die has the design hollowed out. The male die is put on top of the metal, the female die is put on the underside of the metal. The press is forcefully brought down onto the dies and metal, forcing the metal into the shape of the mold. Many medallions and mass-produced jewelry findings are made this way.

Drop Cut

A drop cut (or briolette) is a pear-shaped cut gemstone with triangular facets on top. This type of stone makes a nice pendant.

Edwardian Period

The Edwardian period (also known as the Belle Epoque) was the time of the reign of Edward VII of England (1901-1910). Edwardian jewelry is delicate and elegant. Edwardian designs frequently use bows and filagrees. Pearls and diamonds were also frequently used.

Emerald

Emeralds are a very hard, green precious stone (beryl, Be3Al2Si6O18, colored by chromium and some vanadium impurities). Flaws and cloudiness (called jardin) are very common in emeralds, so many emeralds are oiled, irradiatied,and dyed to improve their look. Synthetic emeralds (developed by Carroll Chatham in the 1930's) have fewer imperfections and are very hard to distinguish from natural emeralds. Emeralds belong the beryl group of stones which also includes aquamarines, morganite, and chrysoberyl). Emeralds have a hardness of 7-8 and a specific gravity of 2.6 - 2.8. Emerald (and all forms of beryl) have large, perfect, six-sided crystals. Emeralds were long thought to have healing powers, especially for eyesight. During the renaissance, emeralds were used as a test for friendship among the aristocracy; an emerald given to a friend would remain perfect as long as the friendship endured.

Emerald Cut

Emerald cut stones have a girdle that is rectangular with truncated corners. Emerald cuts are frequently used on emeralds and diamonds.

Enamel

Enamel is a glassy substance (powdered glass with colorants) fused onto metal using heat

Eternity Ring

An eternity ring is a narrow ring with a ring of gemstones.

Etruscan Jewelry

Ancient Etruscan jewelry has intricate and beautiful designs; most is made of gold. The Etruscans employed a lot of delicate granulation (n which tiny beads of gold are soldered to the surface to form a pattern) and openwork filagree (in which filagree patterns are not applied over sheet metal). The Etruscans lived in Northern Italy for hundreds of years beginning in the late 8th century B.C.

European Cut

The European cut (also known as the old European cut) is an old, round diamond cut that is similar to but less bright than the newer brilliant cut. The European cut has a very small table and heavy crown.

Facet

A facet is one of the flat surfaces of a cut stone or glass.

Faceting

Faceting is the cutting and polishing of the surface of a stone.

Fancy Cut

Fancy cut stones are cut in unusual ways. Some fancy cuts include the heart, fan, rivoli, trapezium, cathedral window, half-moon (lunette), kite, and triangle.

Fashion Jewelry

Fashion jewelry is another name for costume jewelry.

Feather

A feather is an internal flaw (also called an inclusion) in a gemstone that can start at the surface of the stone and extend deep inside. Feathers can either ruin a stone (by making it fragile and/or changing the color), or add to its beauty.

Filigree

Filigree is gold or silver wire that have been twisted into patterns and soldered into place. Openwork filigree is not soldered onto a sheet of metal and is difficult to make. Imitation filigree is made of stamped metal.

Fire	A stone's fire is the streaks of brilliant color within it. Good quality opals have a lot of fire.

Fire Opal

Fire opals are a type of opal that is firey orange to red in color (but have no opalescence). These opals are rarely transparent - they are usually milky. Opal is a mineral composed of silica (and some water) and is a species of quartz. 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 hardness of 5.5 to 6.5 and a specific gravity of 1.98-2.50. Fire opals are found in Western Australia, Mexico, Brazil, Guatemals, and Honduras.

Flaw

A flaw is a an imperfection in a gemstone. Flaws include: cracks, inclusions of other minerals or liquid-filled cavities. A flawless stone is called "clean." Flaws can greatly reduce the value of a stone, but in some cases, like moss agate or rutilated quartz, the "flaws" increase the value of the stone.

Flourescence

Fluorescence is property in which light (or other radiation) is emitted from an object. Many stones (including some diamonds) flouresce when exposed to ultraviolet light.

Freshwater Pearl

A freshwater pearl is a pearl that was harvested from a freshwater mussel (a mollusk). These pearls are frequently shaped like crisped rice cereal, and are less valuable than oyster pearls. Biwa pearls are very good quality freshwater pearls.

Full Cut

A full cut stone is a gemstone with 58 facets.

Garnet

Garnets are any of a group of semi-precious silicate stones that range in color from red to green (garnets occur in all colors but blue). Some garnets used as gemstones include pyrope (the deep red garnet), almandine, spessartine, grossular, the iron-aluminum dark red garnet (also known as the carbuncle stone), Uvarovite (rare), and the lustrous Andradite (which includes the valuable green demantoid garnet, Topazolite , and Melanite). Red garnet is the birthstone for January. Garnet has a hardness of 6-8 and a specific gravity of 3.5 - 4.3.

Types of Garnet:

Grossular - Colorless, orange, yellow, pink, or brown
Pyrope - Colorless, pink, or red
Pyrope Almadine - Red-orange to red-purple
Almandine spessartine - Red-orange
Chrome pyrope - Orange-red
Almandine - Orange-red to purple-red
Hessonite - Yellow-orange to red
Spessartine - Yellow-orange
Topazolite - Yellow to orange-yellow
Malaia - Yellow to red-orange to brown
Andradite - Yellow-green to orange-yellow to black
Demantoid - Green to yellow green andradite
Tsavorite - Green to yellow-green
Pyrope-Spessartine - Green-yellow to purple
Color-change garnet - Blue green in sunlight; purple-red in incandescent light
Transvaal "jade" - Bright green grossular garnet
Uvarovite - Emerald green
Grape - purple
Rhodolite - Purple-red
Xalostocite - Pink grossular garnet

Gemstone

A gemstone (also called a precious stone) is a mineral that is valuable, rare and often beautiful. A few organic materials, like amber, coral and pearls are also considered gemstones.

GIA	GIA stands for the Gemological Institute of America.

Girdle

The girdle is the widest perimeter of a gemstone.

Guilloche

Guilloche is a type of enameling in which translucent enamel (fused glass) is applied over a metal surface that has been engraved. The Czech guilloche pin above is studded with marcasites.

Hallmark

A hallmark is an official mark (or a series of marks) made in metal that indicates the fineness of the metal and the manufacturer's mark. For example, a hallmark of 925 indicates 925 parts of gold per 1000 weight. Other hallmarks indicate the maker of the piece and sometimes the year of manufacture. In many countries (like Britain) it is illegal to hallmark metal incorrectly; some countries are notoriously lax in their enforcement of hallmark honesty.

Hammered Metal

Hammered metals have been formed, shaped, or decorated by a metalworker's hammer. The surface of hammered metal is covered with crater-like depressions made by a hammer. Many hammered metals are used in jewelry including gold, silver, brass, alumimum, etc.

Hardness

A substance's hardness is how resistant it is to being scratched. Hardness is measured using the Mohs Scale of Hardness. In the Mohs scale, one substance is harder than another if it can scratch it. For example, a diamond will scratch garnet, but not the other way around, so a diamond in harder than garnet.

Heat Treatment

Heat treatment is the heating of stones to a high temperature in order to enhance the color or clarity. For example, blue-green aquamarine becomes blue with heat treatment and brown zircon becomes blue or clear. chromium .02%, and zinc .02%; the remaining 0.16 percent is sulfur, chlorine, and water.

Inclusion

An inclusion is a particle of foreign matter contained within a mineral. Inclusions can be solid, liquid, or gaseous. Many inclusions decrease the value of a stone, but some, like rutile forming asterisms in star sapphires and needles in rutilated quartz and tourmalinated quartz, are prized.

Inlay

An inlay is a piece of material (often stone or glass) that is partially embedded in another material (usually metal) such that the two materials make a level surface.

Iolite

Iolite, also known an water sapphire, 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 is not rare and has a hardness of 7 - 7.5. Iolite is found in Sri Lanka, India, Madagascar and Burma.

Irradiated Diamonds

Irradiated diamonds are diamonds that have been exposed to radiation. This changes the diamond's color (as the radiation changes the crystalline structure of the diamond). The change in the diamond is permanent. Older radiation treatments involving exposing the stone to radium; newer treatments bombard the stone with atomic particles in a cyclotron (which accelerates protons, neutrons, or alpha-partices to high speeds). The irradiated stones take on a greenish or an aquamarine hue. Irradiations of diamonds was first done in 1904 by Sir William Crookes, who exposed diamonds to radium, giving them a permanent greenish color; his diamonds are still slightly radioactive (at the level of radium-painted watch). Newer irradiation techniques bombard the crystal with atomic particles in a cyclotron, and then the stone is heated to about 800 degrees Centigrade, producing a stone with very little radioactivity and a permanent color change.

Irradiation

Irradiation is the act of being exposed to radiation. Many stones (like kunzite) are irradiated in order to enhance their color. Being irradiated changes the crystal structure of the mineral by moving electrons. Irradiation techniques bombard the crystal with high-energy radiation (like gamma rays), producing a stone with very little radioactivity and a change of color. Some color changes caused by Irradiation are permanent, others care unstable and be reversed by heating or exposure to sunlight. For example, colorless topaz changes to a cinnamon brown color after ibeing irradiated with cobalt-60 radiation, but the color fades as the stone is exposed to sunlight. A new method of irradiation changes clear topaz to a brilliant, non-fading blue.

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).

Knot	A knot is a flaw (a mineral inclusion) in a gemstone (usually a diamond) that is at the surface of a gem after polishing. The knot is a small raised bump on the finished gemstone.

Kunzite

Kunzite is a transparent pink, light pink, or light purple gemstone that resembles roze quartz. It is a variety of the mineral spodumene. Kunzite can fade after prolonged exposure to light. Kunzite is also called "evening stone," because of its propensity to fade in bright light. The original color of some kunzite stones can be restored or even intensified by irradiation. It is usually used as a large stone and is easily chipped; small stones of kunzite are difficult to cut. Kunzite is often used in pendants. Kunzite has a hardness of 6-7 and a specific gravity of 3.1 - 3.2. Kunzite was first found in 1902 in Pala, California, USA, and is named for the gemologist George F. Kunz. Kunzite's chemical composition is LiAlSi2O6

Lapidary

A lapidary is someone who cuts and polishes gemstones.

Lapis Lazuli

Lapis lazuli is a rich blue opaque, semi-precious stone that has been used in jewelry since ancien times. Ground-up lapis lazuli was once used as a pigment for oil paintings. Lapis lazuli is often dyed to deepen and improve its color. Lapis has a hardness of 5.5; it chips and scratches easily. It has a specific gravity of 2.4 to 2.9. Water can dull its sheen. Lapis lazuli contains the minerals calcite (which decreases its value), pyrite (which can increase its value), and sodalite. Swiss lapis is not Lapis lazuli at all; it is dyed jasper. Denim lapis is relatively pale, low-grade, inexpensive lapis from Chile; it is the color of denim cloth because of calcite inclusions (which whiten the color and lower the value).

Lost Wax Casting

Lost wax casting is a process of casting metal in which the original model is sculpted in wax. The wax is then enclosed in clay and the wax is melted out, making a hollow mold. The mold is then filled with molten metal. The clay is broken off and the cast metal remains. This method of casting has been used for at least 4,000 years.

Luster

A stone's luster is its sparkle or sheen - the way it relects light. The luster depends on the nature of the stone's surface reflectivity. Some types of luster include: adamantine (also called brilliant or diamondlike, like a faceted diamond), earthy (with little reflectivity- also called dull, like shale or clay), greasy (like nepheline or apatite), metallic (also known as splendent, like pyrite or marcasite), resinous (like amber), pearly (with an iridescent reflectivity, like pearls or mica), pitchy (tarry minerals that are radioactive, like uraninite), silky (with a fibrous structure, like some tiger's eye or satin spar), vitreous (also known as glassy, like olivine, transparent quartz, or obsidian), and waxy (like halite or turquoise). A pearl's luster is derived from its nacre.

Marquise

Marquise cut stones have a shape like an oval with two pointed ends.

Matte Finish

A matte finish on a metal's surface is a soft, lustrous finish that reduces the metal's reflectivity.

Melee

A melee is a small diamond, under .20 carat.

Millegrain

A millegrain (or millegrain setting) is a setting in which the stone is secured by tiny beads [grains] of metal or a band of metal that is decorated with tiny beads of metal.

Milling

Milling is a process in which wood or metal is cut while it either the material or the tool is spinning. Symmetrical shapes and patterns are cut into the material.

Mine Cut

Mine cut stones have a cushion-shaped girdle. This type of cut was popular in the late 1800's.

Mohs Scale

The Mohs Scale of Hardness measures a substance's hardness, that is, how resistant it is to being scratched. In the Mohs scale, which ranges from 1 to 10, one substance is harder than another if it can scratch it. For example, a diamond (hardness = 10) will scratch garnet (hardness = 6.5-7.5), but not the other way around, so a diamond is harder than garnet. This scale was invented by Austrian mineralogist Friedrich Mohs (1773-1839).

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 hardness of 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.

Nacre

Nacre is a usually whitish crystalline substance which oysters, mussels, snails, and other mollusks secrete around a foreign object (like a tiny stone) that has made its way into their shell. As layers of nacre coat the intruder, a pearl is formed over a period of many years.

Natural Pearl

A natural pearl (also called a genuine pearl) is a pearl that was produced in an oyster, freshwater mussel or other mollusk as a reaction to a tiny invading object that happened to be caught inside its shell.

Noble Metals

The noble metals are gold, platinum, and silver. These are metals that are relatively impervious to chemical action.

Old Mine Cut

Old mine cut is a term that refers to a brilliant cut in which the stone is cushion-shaped and has a high crown (the upper part of a gemstone).

Onyx	Onyx is a semi-precious stone that is black and white, generally arranged in layers. It is a form of agate with parallel banding. This structure lends itself to cameo making. Onyx is a species of chalcedony (microcrystalline quartz).

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 firey 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). Opals have a hardness of 5.5 to 6.5 and a specific gravity of 1.98-2.50. Opals are found in many placees worldwide, but Australia has a tremendous variety of beautiful opals.

Opera-Length

An opera-length necklace is a single strand that is from 30 to 35 inches (60 to 90 cm) long. Opera-length generally refers to a string of pearls that hangs to the breastbone.

Oxidation

Oxidation is a chemical process in which oxygen atoms bond to atoms of a material (like a metal) and electrons are transferred from the oxided material to the reduced material. Iron oxidizes when exposed to air and moisture, forming iron oxide (rust). Silver oxidizes (tarnishes, turing the surface black) when it is exposed to hydrogen sulfide in the air (forming Ag2S, silver sulfide).

Padparadscha Sapphire

Padparadscha sapphires (also spelled padparadschah) are a rare pink-orange variety of corundum or the synthetic equivalent. These gems are mined in Sri Lanka and are usually heat treated to improve and intensify the color. The name padparadscha comes from the Sinhalese word for lotus flower. Hardness = 9, Specific Gravity = 4.

Palladium

Palladium is a valuable, durable, and malleable light-gray metal used in some jewelry; it is related to platinum, but is less dense and has a lower melting point. Unlike platinum, palladium reacts when exposed to aqua regia, sulfuric, nitric, and hydrochloric acids. It also develops a tarnish when it is heated. Pallasium is not a shiny as platinum. Palladium was only isolated as an element in 1802 by William Hyde Wollaston and Smithson Tennant. It was first used in jewelry in 1939 (during World War 2, platinum was used for war purposes, and was not available for jewelry making - palladium was temporarily used as a substitute for platinum). White gold is sometimes alloyed with palladium (instead of nickel), resulting in a gray-white gold. After World War 2, palladium was rarely used in jewelry making because of some difficulties in working with it. Palladium was recently discovered to be useful in engine catalytic converters, and its price skyrocketed to over $700 per ounce (it had previously been much less expensive than platinum or gold) and is no longer practical to use as jewelry.

Pave	Pave settings are stones set very close together. The stones hide the underlying surface. In better pieces, claw settings are used; in less expensive pieces, the stones are simple glued in.

Pavilion

The pavilion is the lower part of a cut gemstone, below the girdle.

Pear Cut

A pear cut gemstone (also called a drop cut) is teardrop shaped This type of cut is used for pendants, drop earrings, rings, and other pieces of jewelry.

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).

Pendant

A pendant is a hanging ornament. Necklaces, pins, and earrings often have a pendant. The Christian Dior pendant shown above is costume jewelry.

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.

Plating

Plating or electroplating (also called Galvanotechnics after its inventor, Luigi Galvani) is a process in which one metal is coated with another metal using electricity. In jewelry, inexpensive metals are frequently electroplated with more expensive metals, like gold (gold plating), copper (electrocoppering), rhodium (rhodanizing), chromium (chromium plating), or silver (silver plating). The thickness of the metal coat varies. Electrogilded coating is the thinnest (less than 0.000007 inches thick); gold-cased metals have a coating thicker that 0.000007 inches.

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. Platinum is related to iridium. Platinum is 60% heavier than gold. Iridium and platinum are frequently alloyed together, since the Irridium increases the workability of the platinum. Platinum was only discovered in the 1700's in Russia. Platinum is abbreviated Pt. and Plat.

Point

A point is a hundredth of a carat or 0.002 gram.

Precious Stone

A precious stone (also called a gemstone) is one that is valuable and rare.

Princess Cut

A princess cut is a square-cut stone. This fancy cut is relatively new and is also known as a Quadrillion or Squarillion cut.

Promise Ring

A promise ring is a pre-engagement ring, usually with a relatively small stone.

Radiant Cut

The radiant cut is a method of cutting rectangular stones so that they have the sparkle of brilliant cut round stones. The shape is a rectangle with the corners clipped off - the length:width ratio is usually from 1.5:1 to 1.75:1. This cut has from 58-70 facets; it was invented in the 1970's. The top of the stone is emerald cut (with about 25 facets above the girdle), but the bottom of the stone has brilliant cut facets (with about 36 facets below the girdle).

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.

Rhodium

Rhodium is a white precious metal. Rhodium is extremely expensive and is often used to plate precious and base metals, giving jewelry a hard, platinum-like sheen.

Rhodolite

Rhodolite (meaning rose stone in Greek) is a purple-red to pink-red variety of garnet and is a combination of almandine and pyrope (it is sometimes called pyrope-almandine garnet). This silicate stone has a hardness of 7-7.5 and a specific gravity of 3.5 - 4.3. The formula for garnet is: A3B2(SiO4)3. Rhodolite is found in the US, Zimbabwe, Kenya, and Sri Lanka (Ceylon). Rhodolite is not enhanced.

Rose Cut

The rose cut (also called the rosette cut) for diamonds was invented in the 17th century and its used continued until the 18th century. The rose cut has a flat base and triangular facets (usually 24). This cut has little wastage of stone, but is not nearly as reflective as the brilliant cut, which was invented later.

Rose Gold

Rose gold (also known as pink gold) is gold with a pink tinge. It has been alloyed with a mix of 90% copper and 10% silver.

Rough

Rough stones or crystals are in their natural state, they are neither cut nor polished.

Rubellite

Rubellite (sometimes spelled rubelite) is a red variety of tourmaline. Rubellite is red in both incandescent and daylight, and is more valuable than other varieties of red tourmaline. Rubellite has a hardness of 7-7.5 and a specific gravity of 3.02-3.25. Rubellite is sometimes treated with fillers to increase the clarity of the stone.

Ruby

Rubies are precious stones and a member of the corundum family. 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 (Montana and North Carolina), and Zimbabwe (Rhodesia)

Safety Chain

A safety chain is a secondary closure (usually on a fine bracelet or watch) that is used in case the primary clasp opens, preventing the loss of the bracelet. It is usually a chain that is permanently attached to one side of the bracelet, and attaches to the other side with a spring ring clasp (or other type of clasp). On the Miriam Haskell cuff bracelet above, the safety chain is located on the lower left of the picture.

Safety Clasp

A safety clasp is a secure type of closure on a piece of jewelry. The term safety catch is used for a variety of these closures. On pins and brooches, a safety clasp often refers to a long pin on a hinge that can be held or released with a secure clasp (often a rotating circle within a circle).

Sapphire

Sapphire is a precious gemstone (a type of corundum) that ranges in color from blue to pink to yellow to green to white to purple (mauve sapphire) to pink-orange (padparadscha sapphire). Six-sided asterisms sometimes occur in star sapphires (caused by inclusions of tiny, thin, parallel needles of rutile). Sapphires are related to rubies. Sapphires were once thought to protect the wearer from poisonous creatures. Sapphire has a hardness of 9 and a specific gravity of 3.9 - 4.1. Sapphires are often heat treated to improve their color.

Satin Finish

A satin finish on a metal is between a matte finish and a brilliant one. This semi-glossy finish is done by making shallow parallel lines on the surface of the metal, reducing its reflectivity.

Seed Pearl

Seed pearls are tiny, round pearls that are less than 2 mm in diameter and weigh under 1/4 grain. Seed pearl jewelry was popular from the mid- to late-Victorian era, when the tiny pearls were strung on horsehair to form intricate designs and were also used as accents on other jewelry.

Setting

A setting is a method of securing a stone (or other ornament) in a piece of jewelry (or other object). There are many different types of settings, including the collet (a strip of metal surrounding the stone), the claw setting (in which prongs of metal hold the stone in place), Tiffany (a high,six-pronged setting), the cut-down setting (metal is worked around the edge of the gem, reinforced with metal ridges), pav?-set stones (stones set close together, showing no metal between them), millegrain (the stone is secured by small beads [grains] of metal), gipsy setting (with a recessed stone), and many other types (including combinations of the above-mentioned methods). Some settings are closed (there is metal behind the stone), while others are open (there is no metal behind the stone), letting light shine through the stone.

Shank

The shank is the part of a ring that encircles the finger.

Solitaire

A solitaire is a ring set with a single stone, usually a diamond.

Star Ruby

A "star ruby" is a ruby that exhibits an asterism, a six-pointed star of light (when cut as a cabochon). The world's biggest star ruby is the Rajaratna, which weighs 2,475 carats. The world's biggest double-star ruby (with a 12-pointed star) is the Neelanjali, weighing 1,370 carats.

Star Sapphire

A star sapphire is a sapphire that exhibits an asterism in the form of a colorless, six-rayed star that reflects light. Star sapphires are cabochon cut. Laboratory-produced star sapphires ("Linde stars") were developed in 1947 by the Linde company; most star sapphires today are synthetic.

Step Cut

The step cut is generally used for colored stones. This cut is rectangular to square and has many facets parallel to the edges of the stone.

Sterling Silver

Sterling is silver with a fineness of 925, that is, sterling is 925 parts per thousand (or 92.5%) silver and 7.5 parts per thousand (or 7.5%) copper (the copper increases the silver's hardness). Sterling is quite malleable.

Striations

Striations are grooves, lines and scratches found naturally in some minerals.

Table

The table is the large, flat area at the top of a cut gemstone.

Tahitian Pearl

Tahitian pearls (also called black 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).

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.

Tennis Bracelet

A tennis bracelet is a simple, flexible, in-line diamond bracelet. The name tennis bracelet was first used when the great tennis player Chris Evert dropped a diamond bracelet during a tennis match in the summer of 1987 (at the US Open Tennis Tournament). She had to stop the match until she found her bracelet. Since then, that style of bracelet has been called a tennis bracelet.

Tiffany Setting

The Tiffany setting is a ring with a high, six-pronged solitaire diamond on a simple circular band. This design was introduced by Tiffany & Co. in 1886.

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.

Tourmaline

Tourmaline is a dichroic gemstone that comes in many, many different colors; it also appears to have different colors depending on the angle at which it is seen. Tourmaline has the greatest color range of any gemstone - thel ighter colors are more valuable than the darker colors. It ranges in color from pink to green to red (rubellite) to purple to blue-green (indicolite) to colorless (achroite) to black. Watermelon tourmaline is both pink and green. Tourmaline occurs as an elongate three-sided prism and is mined in Brazil, The Ural mountains in Russia, Namibia, Sri Lanka, and California. Tourmaline was only discovered in the 1700's. Tourmaline has a hardness of 7-7.5 and a specific gravity of 3.02-3.25. It is doubly-refractive.

Trillion Cut

The trillion cut is a triangular cut based upon a brilliant style cut (and not a stepped facet). The corners of the triangle are truncated (cut short) and there are a variety of facets, giving this cut a sparkling brilliance.

Tsavorite

Tsavorite is a rare, deep green variety of grossular garnet, a type of garnet, calcium-aluminum silicate. The emerald green color comes from vanadium and chromium. Tsavorite is similar to emerald, but is rarer and more durable; it also has a higher refractive index, 1.74. Tsavorite stones over two carats are considered large and are very rare. Tsavorite has a hardness of 7.5 and a specific gravity of 3.6. Tsavorite is found in east Africa; it was named by Harry B. Platt of Tiffany & Co. for the Tsavo National Park in Kenya, where this gemstone was originally found in 1967. Tsavorite is not enhanced.

Turquoise

Turquoise is a non-translucent, porous semi-precious stone that is usually cut as a cabochon. Turquoise was first found in Turkey, hence its name. Turquoise is found in desert regions worldwide. Persian turquoise is robin's egg blue and has no matrix (streaks of the mother stone from which they were found). North American turquoise is greener and has a matrix streaks. Over the years, oil from your skin is absorbed by the stone and it will change color slightly. Turquoise has a hardness of 6 and a specific gravity of 2.60-2.85.

Watermelon Tourmaline

Watermelon tourmaline is a tourmaline gemstone that is multicolored, going from pink to green. The Schreiner pin above is made of paste (glass) watermelon tourmaline.

White Gold

White gold is gold that has been alloyed with a mix of nickel, zinc, copper, tin, and manganese (and sometimes palladium). White gold was originally developed to imitate platinum during World War II (during this time in the US, platinum was considered a strategic material and its use was prohibited for most non-military applications, like jewelry making).

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.