AFRICAN EMERALD: A common term for a green-colored fluorite, found in South African mines. Unlike it name implies, such stones are usually not actually emeralds.

AGATE: A gemstone, which is when sliced, resembles the growth rings of a tree, though some samples of agate instead of rings have spots of color. Agate is a form of multi-colored layers of chalcedony quartz and sometimes is a filling in cavities of other rocks. The rings in the agate texture can be of different width and textures.

ALEXANDRITE: First discovered in Russia, and named in honor of Tzar Alexander II, Alexandrite is rare gemstone, belonging to the chrysoberyl family of minerals. Though in daylight it may appear in shades of blue and green it is most well know for dramatically changing its color in different types of lighting.

ALLOY: The result of combining various metals, which possesses different, often better characteristics than those of its original component.

ASSAY: A test performed on alloys to determine the percentage of precious metal from the total amount of its contents.

ASSCHER: A method of cutting diamonds, invented by Joseph Asscher, in whose honor it is named. In its appearance a stone cut in this method resembles an octagone Due to its square cut with 72 wide step facets and deep clipped corners.

AQUA REGIA: A mixture of hydrochloric acid (3 parts) and nitric acid (1 part), one of the few that can dissolve gold and platinum, usually used to test the purity of those metals.

BAGUETTE: From French "rod", a method of cutting gemstones, which creates a stone that appears as a long rectangle.

BAROQUE PEARLS: Irrelevant of the nature of their origin, refers to the irregularly shaped pearls.

BIRTHSTONES: A set of twelve gemstones that is associated with months of the year, or more precisely, specific zodiac signs. Different sets of stones are used by different cultures.

Find out more in the Birthstones section of the Education center.

BEZEL: The faceted portion of the cut gem, located on top, above the girdle and below the table .

BLUE GOLD: A term used to describe an alloy, consisting of 75% 18K gold and 25% iron. The resulting alloy has a bluish ting.

BRUSHED FINISH: A finishing technique usually used to add texture to jewelry made out of metal, which produces a somewhat less reflective surface. This is accomplished by running a stiff metal brush along the surface.

CARAT: Carat is the standard unit of weight used for diamonds and most other gemstones. One carat equals .200 grams (or 200 milligrams). The larger the total amount of carat, the rarer and consequently more valuable is the stone.

CLARITY: Clarity is a term that is used to describe a relative freedom from flaws and blemishes on the inside and on the surface of a diamond or a gemstone. A perfect stone with perfect clarity (clearness) is rare, and most flaws that exist in jewelry grade diamonds cannot be seen without looking at stones through a jeweler's magnifying loupe.

CROWN: The portion of a cut stone that is located above the girdle.

CULET: A miniature facet found at the bottom of some gemstones, which could also be regarded as the pointed portion of the stones base.

CULTURED PEARL: Cultured pearls are formed when a piece of mother-of-pearl or other particle that is manually placed inside a shell of a river or marine mollusk (select types of oysters and clams.) To protect itself from the intrusion the mollusk coats this particle in layers of a material known as nacre, or mother-of-pearl, like an onion skins. This process of layering eventually builds the particle up to form a beautiful pearl. Cultured pearls vary in shape depending on the shape of the piece being coated. Cultured pearls are sold by their size in millimeters.

DIFFUSION: A process used to enhance the color of a gemstone by applying a temporary coating onto its surface.

DOUBLET: Most commonly used with Opals, doublet is a layering of a small amount of a valuable stone on top of a cheaper stone or glass.

ENAMEL: A hard surface, used for decoration, and created by placing glass ground into powder onto metal and firing this combination in a kiln to melt the glass powder and fuse it to the metal.

ENGRAVING: A process of applying words or decorative images on jewelry made out of metal. This process may be done by hand or by mechanical tool, called a graver.

FACET: One of the small, smooth, flat or nearly flat polished areas cut on a gemstone or occurring naturally on a crystal.

FLUORESCENCE: A characteristic that makes some diamonds appear to change color when they are exposed to ultraviolet light. Since UV radiation is a component of daylight and is also present in fluorescent lit rooms, the stone could change color under those conditions.

• Stones that produce a blue reaction will probably appear whiter, or more colorless, under UV light.
• Stones that fluoresce yellow will appear even more yellow under some lighting conditions.

FRACTURE FILLING: A treatment which utilizes clear, glasslike substance to seal up small cracks in the surface of gemstones. Such treatment does not eliminate cracks, but only masks them to an unaided eye.

Fracture filling is not permanent, and can wear away.

FRACTURES: Cracks that occur on the surface of gemstones and may appear as white areas.

GIRDLE: The area of a stone which is usually clenched by the prongs of a setting, and is the edge formed where the top (crown) and bottom (pavilion) of a stone meet.

GOLD PLATED: piece of jewelry made out of metal that is covered by a think layer of gold.

IVORY: The term usually used to refer to a white or cream colored material, which is made out of the tusks of various animals, including elephants, mammoth and walrus. Most of such animals are on the endangered list; therefore most trade in ivory, other than in authentic antiques, is prohibited in the US.

INCLUSION: Also known as a flaw, an inclusion is an internal imperfection in a gemstone.

JET: Black fossil coal or wood, whose texture allows to be easily carved into different pieces of art including jewelry. Depending on the finishing method jet may be opaque or polished in appearance.

KARAT: K (karat) is a unit of purity of gold; it consists of 24 parts, and lets us know what portion of the alloy is pure gold. For example 18K gold is 18/24, or 75% pure gold.

LASER DRILLING: Process by means of which the clarity of diamonds can be improved by using lasers to remove flaws from the stone.

LOUPE: Pronounced as loop, it is a special magnifying glass that allows to take a closer look at your gemstone, or any other object you might be interested in. It magnifies the gemstones to allow us see the flaws and blemishes outside and inside of the gemstones. The loupe also permits you to evaluate the stones color and cut.

MILLEGRAIN: A technique of applying miniature beads of metal. As well as being used to secure gemstones in their setting this method is also used as decoration, without the use of gemstones.

MOTHER OF PEARL: The iridescent material that could be observed on the inside of the mollusk or oyster shells. As a defense mechanism against intruders in most oysters and mollusks a substance gets secreted within the shell, which is known as nacre. This substance lines the walls of shells, and is also the matter layers of which form pearls.

NATURAL GEMSTONE: A gemstone formed in nature, without any assistance from humans.

NATURAL PEARL: Natural pearls are formed when a piece of sand or other particle that ends up inside a shell of a river or marine mollusk (select types of oysters and clams.) To protect itself from the intrusion the mollusk coats this particle in layers of a material known as nacre, or mother-of-pearl, like an onion skins. This process of layering eventually builds the particle up to form a beautiful pearl. Natural pearls vary in shape depending on the shape of the piece being coated. Natural pearls have always been considered rare and are quite expensive. They are usually sold by carat weight. Most natural pearls on today's market are vintage pearls.

NOBLE METALS: Term sometimes used to refer to precious metals like silver, gold, and platinum.

ORGANIC JEWELRY: Jewelry that is created by living organisms or from previously living ones.

OILING: A technique of sealing up cracks and fractures in gemstones; sometimes used to improve clarity of emeralds, as well as seal opals from water loss.

PAVILION: The bottom section of a cut gemstone, which begins at the girdle and continues to the point at its end.

PLATING: Also known as electroplating and Galvanotechnics, plating is a process of covering one metal with another, utilizing electricity.

PLATINUM: Platinum is rarer, and therefore more expensive, than gold. It is 60% heavier than gold, grayish-white in color, non-tarnishing, and very strong. Very high temperatures are necessary to melt platinum; therefore, it did not become a viable jewelry metal until advancements in jewelers' tools were made in the late 1800s. Jewelry platinum is an alloy, usually 90% platinum and 10% iridium. Platinum jewelry is typically stamped "Plat."

PINCHBECK: Pinchbeck (also known as "false gold") is an alloy of copper and zinc, which looks like gold. It was invented by the British watchmaker Christopher Pinchbeck (1672-1732). Pinchbeck consists of 83% copper and 17% zinc.

PRECIOUS METAL: Rarely occurring in nature metals that include silver, gold, and metals from the platinum family.

RHODIUM: A precious metal, belonging to the platinum family, white in color and quite rare. Due to its high cost Rhodium is most often used to plate jewelry made out of metal, giving them a grayish, platinum-like luster.

RUSSIAN GOLD FINISH: A finishing method for jewelry made out of metal that produces a matte, antique look.

SATIN FINISH: A finishing method for jewelry made out of metal that produces a semi-gloss finish. In appearance it is between the matte finish and a luminous polish. This effect is achieved by reducing reflective appearance of the metal as a result of making very shallow, tiny parallel lines on the surface of the metal.

SETTING: The section of a piece of jewelry, that holds the base of gemstone in place. Settings could be closed and open, where closed refers to the fact that there is metal behind the stone, and the open refers to the settings where there is no metal behind the stone.

STAR FACET: One of the eight small triangular facets in the crown of a gemstone with an "Ideal" cut.

STERLING: An alloy of silver and copper resulting in very malleable and ductile product, which is harder than silver. Sterling Silver contains 925 parts per 1000 (92.5%) of silver and 75 parts per thousand of (7.5%) copper.

SYNTHETIC GEMSTONE: Artificially created gemstones, developed in a lab to imitate the chemical and physical structure of naturally occurring gemstones.

TABLE: The flat top of a cut stone, also sometimes called its face.

TORSADE: A type of necklace which is made by using several strands and twisting them together.

VERMEIL: Pronounced as ver-MAY, is a product of sterling silver coated or plated with gold on its surface. At least 10K gold is used for coating, with the plating layer being at least 2.5 microns thick.

WELD: A process that usually employs a torch to create high heat or order to joins two pieces of metal.

WHITE GOLD: A term used to describe an alloy usually made by combining gold with a mixture of copper, manganese, nickel, tin and zinc, and sometimes palladium. The resulting alloy has a grayish color, which resembles platinum.

YELLOW GOLD: A term used to describe an alloy usually made by combining gold with copper and silver.