A Glossary of Gems and Jewelry Terms

A Glossary of Gems and Jewelry Terms

abalone pearls

Pearls found or commercially grown in an abalone (single shelled mollusk).

acorn beads

Type of antique Venetian glass bead with distinctive vertical ridges.

adularescence

African emerald

Actually a green variety of fluorspar that is mined in South Africa.

African jade

A green-colored, dense variety of garnet.

African trade beads

Derive their name from a past use in parts of Africa as currency. Also known as money beads.

The name agate comes from the Sicilian river formerly called Achates. The Drillo river (modern name of the Achates) is still a major source of this form of chalcedony. Early civilizations, including the ancient Egyptians, used agate for seals and protective talismans. Earlier civilizations created eye beads by carving a hole through an agate disc to symbolize the lens of an eye.

Jewelry used to adorn hats or hair and is designed in the shape of a feather plume.

alexandrite

Discovered in the Ural Mountains in 1830 on the birthday of Czar Alexander, which explains its name. It is valuable because of its rarity and because it contains crystals that, because of their light-absorbing qualities, cause the stones to change colors under different lighting.

allochroite

A garnet that is dark-colored due to its iron-lime composition.

An alloy that is used as a substitute for silver. It is made primarily of copper that is mixed with nickel, tin and zinc.

altered stone

Any stone that has been changed in appearance, particularly in color, by an artificial process; heating, irradiation, and dyeing are some of the processes used to change gemstone appearance.

Not a stone, but rather tree sap that has become fossilized. It is cut, polished and treated as a valuable gemstone, especially when a piece contains a preserved insect. There are two varieties: Butterscotch (found in Eastern Europe) and Brown (found primarily in Siberia).

Its name comes from Greek meaning "not drunk," which stems from a belief that the purple (wine colored) stone could relieve hangovers. This stone is commonly used in necklaces, pendants, rings and bracelets.

A bi-colored variety of crystalline quartz containing the characteristic colors of both citrine and amethyst.

Amorphous means without form and refers to gems such as amber, ivory or jet which don't have a formal internal structure. Opposite of crystalline gems.

Any object worn with the belief that it bestows good fortune or wards off misfortune.

angle of incidence

The angle at which a ray of light enters a stone as measured from normal.

angle of reflection

The angle at which a reflected ray of light leaves a surface as measured from normal.

angle of refraction

The angle at which a reflected ray of light leaves a surface as measured from normal.

anisotropic

Term used in gemology for double refraction.

Appears in a range from light to dark blue or blue-green stone and, in its highest quality, is transparent. It literally means "sea water" and it is a harder stone.

Following (moving in the same form as piece it decorates) scrollwork. It typically appears as curlicues in low relief.

This poison forms a very tight, chemical bond when it is used to color glass (or to remove unwanted color from glass) which makes it completely safe to wear.

A style which features non-natural elements such as sharp angled, geometric shapes, bold colors, molded or faceted beads, as well as the use of chrome and plastics.

art nouveau

Also known as "Victorian" or "Edwardian." This style features fluid lines, natural colors, and natural, particularly floral, themes.

artificial pearls

An obsolete term replaced by the term "cultured," since artificial implied fake or synthetic. See pearls.

artificial stone

A man-made, synthetic or imitation gem.

A star-like light effect that is usually only seen in cabochons.

aurora borealis

Refers to iridescent, faceted glass beads.

Australian jade

See chrysoprase.

A quartzite gemstone, usually comes in green (contains mica) or blue (containing cobalt).

Awabi pearl

Japanese name for abalone pearls.

Similar to malachite, except that it typically appears in a deep and vivid shade of blue.

Beads or rounded stones or glass that are irregularly shaped.

A reddish-brown gemstone which is actually an ore of aluminum. It is found in tropical climates such as Nigeria. Because of it coloring, some African cultures revere it as a symbol of life's force.

A pearl necklace consisting of multiples of twisted strands.

bead setting

A method of securing a facetted stone, it is normally used to secure very small gemstones, usually in multiples.

The supporting ledge of a stone setting.

A finding to which solid beads or stones are glued to make pendants.

An important mineral species that includes aquamarine and emerald.

A thin strip of metal which secures a gemstone on a piece of jewelry; the sloping facets on a brilliant cut gemstone.

A bead with ends that taper off to cones.

A gemstone that designates a wearer's month of birth.

The process of placing the facets on a stone.

A variety of quartz called chalcedony. It exists in different shades of green with red and brown spots caused by iron minerals. The spots look like drops of blood.

The dominant hue within a gemstone.

Bohemian crystal

Glass that has been hardened by adding lead.

Bohemian glass

Glass made in Bohemia, formerly a country in Eastern Europe, which is now part of the Czech Republic.

A chain consisting of rectangular links that resemble books. from the Victorian era.

A term for industrial grade diamonds.

A manufactured (synthetic) gem created by a molten mixture that cools and hardens after being poured into a tear-shaped mold.

box setting

A method of stone setting in which the gem is enclosed in a box and the edges of the metal are pressed down to secure the stone.

Brazilian aquamarine

An alternate name for blue topaz.

Brazilian rock quartz

A gemstone quality variety of quartz found in Brazil.

Refers to a method of cutting gemstones with facets designed to enhance their light reflecting capacity.

An oval or pear-shaped diamond with a surface of triangular facets.

A method of rough-diamond fashioning by rubbing one diamond against another.

A highly polished gemstone with a dome top and no faceting.

cabochon cut

A smooth, rounded cut which does not contain any planes (facets).

calibre cut

Gemstones cut to a specific, standardized size for mounting.

A raised design or figure that is cut out of a gemstone.

A long rod of glass or clay (with or without a pattern) that is used to make beads.

A unit of measurement for weighing gemstones; one carat is equal to .2 grams (note that this term is NOT the same as karat, see below).

A red or brown gemstone that is a variety of chalcedony.

Refers to the technique of reproducing an object in metal from a wax model.

cathedral ring

See cathedral setting.

cathedral setting

A metal band with an arch design that is similar to cathedral arches.

Any type of quartz which has a cloudy, noncrystalline appearance such as agate. Its common colors are blue-gray, white (cream), and red-brown.

change of color

A phenomenon seen in some gems that have a different color in natural light than in artificial light. This color-change is caused by selective absorption and transmission of light.

channel set

A setting composed of either rectangular or square-shaped gems positioned side by side.

The appearance of well-defined bands or threads of light across the surface of a gemstone.

The tendency of opals to crack when exposed to heat or drying air.

A gemstone with a smooth concave depression.

A difficult bead pattern that features layering white, red, and blue glass.

A popular, common name for a small rose-cut or single-cut gemstone.

A short, collar length necklace.

chrysoprase

Refers to a type of chalcedony consisting of a bright green shade that is created by its nickel content. It is a popular choice for use for beads, cameos and cabochons. The highest quality chrysoprase is found in parts of Australia which explains why it is also called Australian jade.

A brilliant mineral of red or vermillion that is often used as a red pigment and which is particularly valued in China where it is frequently used for inlays and in jewelry. The mineral comes from mercury ore.

A type of crystalline quartz which has a color range from pale yellow to a deep orange yellow or brown yellow and also appears from opaque to translucent. This stone is sometimes created by treating amethysts with heat.

claddagh ring

An Irish ring depicting two clasped hands.

A trade term for gemstones that are free of noticeable flaws.

A smooth, flat break or separation in a gem along the direction of its atomic structure.

coated stone

A gemstone covered by an artificially applied transparent material to enhance its color.

Describes the process of filling thin wire partitions (cloisonnes in French) with enamel.

cloud/cloudy

A group of small, white inclusions that give a cloudy appearance to a diamond.

cluster setting

Closely set gemstones arranged to give the illusion of a single, larger gemstone.

cobalt glass

Glass colored with cobalt to create a deep blue color.

A variation on box setting in which the sides of the box are filed away to allow more light to enter the gemstone.

color zoning

Uneven color in gemstones in irregular patches; it can be either different colors or different tones of the same color.

colored stones

A gemstone other than a diamond.

Describes the calcified skeletons of marine organisms that live along coastlines of a variety of salt water bodies such as the Western Mediterranean, Japan, several island groups, and the Red Sea.

Corundum is an aluminum oxide, which is called a ruby when red and sapphire in other colors (including lighter shades of red). The different colors are caused by the presence of chrome, iron, titanium, etc.

cranberry carnelian beads

A rare, antique Venetian glass bead which acquires a true red color by dissolving gold into glass.

critical angle

The greatest angle measured from normal at which light can be refracted out of a stone. Also, a small angle at which light is completely internally reflected.

crown setting

A collet setting consisting of a flared cylinder with one end of the cylinder notched to form prongs.

See lead crystal.

cubic zirconia (or CZ)

Synthetic (artificially created) zircon, commonly used to imitate diamonds.

The extreme low (lowest) point or facet of any stone.

cultured pearls

The specific form into which a stone is fashioned; it is one of the deciding factors in gemstone value.

A raised relief carved into a gemstone in a concave depression.

Czech glass

See Bohemian glass.

damascening

Designs consisting of hard metals inlaid with softer metals.

A bright green variety of garnet.

demi-parure

Matching jewelry containing two or three pieces. See also parure.

An inclusion pattern shaped like a tree or fern.

A diadem is a tiara, a circular or semi-circular piece of jewelry worn on the head.

The separation of light into its spectral colors as it passes through a gemstone.

dogon donuts

Disc beads made from old Dutch cobalt glass by the Dogon, a tribe in Mali, Africa.

double refraction

The separation of a beam of light into two separate beams as it enters a gemstone. The two beams travel at different speeds. It can be used to distinguish one gemstone material from another.

A combination of a lesser value gemstone half glued to, usually, a half of colored glass, resulting in a gem that fakes the quality of a much more valuable stone.

dream beads

A pattern of Venetian glass beads, which features colors and gold particles that appear to be suspended within.

The combined characteristics of hardness, toughness and stability in gemstones; this is one of the deciding factors in gemstone value.

Dutch glass

Beads produced by Dutch traders for commerce, but, because of differences in production, the beads were less durable and colorful than Venetian glass.

A gemstone to which an artificial stain is added to improve color or to imitate a more valuable gemstone.

The proper mineral name for tourmaline. This mineral is named from its original place of origin, Elba Island.

A long, elbow-shaped, Venetian glass bead that was last produced in the 1700s.

Emerald (Greek "green stone"), a hard but brittle gemstone, is the most valuable form of beryl. Colors range from various shades of green, blue green, or yellow green. Colombia is an important source of this gemstone.

Where color substances, melted in a kiln, are used to decorate metal, including metal beads.

Refers to creating a pattern (including writing) on metal.

estate jewelry

Refers to previously owned jewelry (not necessarily antique).

This pattern, also known as the "evil eye" bead, is eldest of bead patterns that were worn for good luck. See agate.

The plane surfaces which form the sides of a crystal.

A small, flat, polished surface on a gemstone.

Cutting a gemstone with a number of flat planes to enhance light reflection. The opposite of cabochon cut.

fancy cut/fancy shape

Any style of gemstone cutting other than the round brilliant or single cut.

fancy diamond

Any diamond with a body color strong enough to be attractive.

A trade term referring to any inclusion within a gem, usually a jagged, irregular fracture that appears white.

feather bead

Glass beads decorated with a featherlike pattern, which originated in Venice, Italy.

See Claddagh Ring.

An amulet, bracelet or pendant in the shape of a person or an animal.

Refers to any jewelry that is designed to look like real objects such as animals, baskets, flowers, humans, etc.

A method for producing delicate, detailed patterns in metal, particularly clasps and bead caps.

Refers to fasteners and construction components that are used in making jewelry.

Italian name for a rose bead. See rose bead.

fingerprint inclusion

Liquid, gas or solid flaws in gemstones which align in the form of a human fingerprint.

The play of color on or within a gemstone as a result of dispersion.

Any visible imperfection within a gemstone.

floater necklace

A bead necklace that uses wide bead spacing and very thin string or line in order to create the effect that the bead(s) are floating.

fluorescence

The emission of visible light when a gemstone is exposed to ultraviolet light. This is a method of distinguishing one gemstone from another and a natural gemstone from a synthetic gemstone.

Thin metal leaf (typically gold or silver) that is used as a backing for imitation gemstones or faceted glass. Foil enhances brilliance and color.

foil backed

The adding of a layer of metallic foil to the back of a gemstone to improve its color or brilliancy.

Four "C"s, the

Refers to the major characteristics in determining the value of a gemstone (usually a diamond): cut, carat (weight), clarity (presence of flaws), and color.

A break or chip in a gemstone in any direction other than along a cleavage plane.

French ambassador beads

Special, knee-length necklaces given to France's ambassadors during the reign of Louis XIV.

French Ivory

Trademark name for granular surfaces celluloid, porcelain or plastic that is used to imitate ivory tusk.

French screwback

A very small, threaded clamp attached to earrings so they could be worn by persons without pierced ears.

full-lead crystal

A higher quality. brilliant crystal that contains at least 30% lead oxide.

A variety of spinel, bluish in color, having a high zinc content.

A gallery is a decoratively perforated metal strip that is either open or closed. Open versions are often modified by jewelers to become gemstone settings.

A gemstone with grain-shaped crystals. It comes in a wide range of colors from black to clear, though its most commonly marketed variety is red.

The study of gemstones, specifically identification, grading, appraisal, marketing, and fashioning.

A precious stone (or pearl) that is suitable to be cut or polished for use in jewelry.

Rock which contains a cavity lined with quartz or other gemstone crystals.

German silver

See nickel silver.

To cover an object with a thin layer of gold.

A gemstone with a glowing, milky sheen that moves as the stone is moved in the path of a light source.

The outer edge of a gemstone.

givre beads

From the French word for frost, they are transparent glass beads that are merged around a translucent core.

A thin layer of melted glass used for decoration and/or protection.

The art of engraving or carving gems.

gold filled

Refers to jewelry containing a common metal such as nickel that is coated with gold.

Two or more chemically related gemstone materials which are similar in structure and physical properties.

gypsy setting

A setting in which the crown of a gem is the only portion exposed and the table of the gemstone is nearly level with the surrounding metal. No prongs or separate bezel is evident because all means of setting the gemstone are below the metal's surface.

hair jewelry

Glass brooches that are used to preserve hair as a decorative keepsake.

hand-knotted

Refers to beads which are strung separately with a knot tied between each bead. This method of stringing creates a more durable strand and reduces wear and tear on the beads.

A gemstone material's ability to resist scratching.

An added finding to secure a gemstone in a prong setting.

Short wires that are used for threading beads onto earrings or pendants.

heat-treatment

Heating a gemstone material to improve its color.

heavy liquid

A liquid of known specific gravity used to test the specific gravity of a gemstone.

See bloodstone.

Refers, generally, to a yellow, orange, brown, golden-brown, or reddish-brown form of (natural) zircon.

illusion setting

A setting in which the surrounding metal's surface is cut or shaped to appear to be part of the gemstone. This technique is often used to enhance the perceived size of small diamonds.

Any foreign mineral or substance "included" within a gemstone. Though generally considered to be flaws, they sometimes enhance the value of certain gems.

India glass

Glass beads from India.

A decoration that is carved into a gem.

The color of a gemstone from bright to dull.

invisible necklace

Ssee floater necklace.

A blue gemstone, named from "ios," which is Greek for violet. Historically used by Vikings to shield their eyes from the sun during sea voyages.

iridescent glass

Glass mixed with arsenic (which safely bonds to glass) to create a rainbow or pearl-like luster.

Describes a thin, air-filled crack within translucent gems that creates iridescence.

See French Ivory.

Material that composes animal teeth, particularly hippopotamus teeth and walrus and elephant tusks.

A form of nephrite that is treasured in China and is believed to bring good luck as well as having medicinal value.

A variety of chalcedony that is usually striped or spotted. In ancient times it was used in seals and to ward off drought.

jasperized wood

Petrified wood. It is wood that has fossilized (where the original wood has been replaced with minerals, resulting in a stone-like wood replica).

jelly belly

A piece of jewelry that has a center made from glass (or clear lucite).

A carbon mineral (lignite coal) that, when cut into facets, has the stunning appearance of a black diamond.

Glass pigmented (colored) with coal.

Job's tears

Refers to the incredibly hard seeds derived from a variety of wild, tropical grass plant. The seeds (white) are transformed into jewelry by a process of drying, coloring and polishing. Typically, they're used to make bracelets and necklaces.

Any small wire ring for connecting or suspending a piece of jewelry.

Refers to an alloy's gold content; 14 karat describes a content of roughly 60% or greater, while "pure" or 18 karat gold, surprisingly, may have as little as 75% gold content. (Not to be confused with the term, carat; see above.)

keeper ring

A ring that is worn with another, more valuable ring. It's placed on the finger after the first ring as a safeguard against loss (slipping off finger).

Refers to a sapphire that appears from yellow to yellow-brown.

Is a type of spodumene that has a lilac-pink color.

General reference to any gem that is manufactured rather than natural.

lampworked glass

Any glass that is hand-shaped from glass canes or tubes which are held over flames. The name came from the fact that the glass was originally (1700s) formed in flames from oil lamps.

Refers to cutting, shaping, polishing precious and semi-precious stones in order to create jewelry. This term is also used to refer to persons who perform these skilled tasks.

A very soft, beautiful, royal blue stone. It is commonly associated with royalty and often appears with bits of calcite (white) or pyrite (gold).

A necklace designed to look like a lasso.

Refers to pendants, gemstones that dangle from a neck chain.

lead crystal

High-quality glass that contains a minimum amount of lead oxide. The higher the lead oxide content, the higher the quality of crystal.

See metallic leaf.

Refers to a cabochon (smooth, no facets) cut stone where the upper and bottom portions are identical.

lobster claw clasp

A spring-loaded jewelry fastener that looks like a lobster claw. It is used to attach separate pieces or separate ends of jewelry or accessories together.

A type of magnifying glass used by jewelry professionals to examine gemstones, particularly diamonds.

The appearance of a surface resulting from reflected light.

A trade term referring to the quality of a gemstone's cut.

A copper mineral with a pattern of dark green and yellow bands. Historically, it was believed to ward off evil or to attract financial success.

Maltese cross

A cross whose four equal-length arms become wider the farther they get from the center.

A form of iron pyrite with a shiny appearance, typically has a faceted surface.

A misleading term for what is actually blue glass.

matinee-length

A single strand necklace with a length of between 22 to 23 inches (56 to 58 cm), a length.

The rock in which gemstone material is found.

maw-sit-sit

A rare gemstone. It is green with dark veins (ranging from deeper green to black) and, sometimes, white spots. It may appear translucent to opaque.

A small (under .20 carat) diamond.

metallic leaf

Extremely thin sheets that are made from rolled or pounded copper, gold, platinum or silver. Leaf is used for applying to base metal surfaces.

A style of setting in which the stone is held in place by a row of tiny beads along the girdle of the stone.

Describes a stone that has its upper and lower portions cut in two different styles.

Moh's scale

A categorization of minerals according to their hardness or resistance to scratching; diamond is the hardest.

mokume-gane

A Japanese metal-work technique that gives precious metals a wood-like appearance.

A rare, glassy, translucent, dark green gemstone that is made of a mineral that is similar to silica. It is rock material that was fused during the impact of a meteorite.

molded cameo

Cameos created by molding rather than carving. Usually is made from pouring glass, plastic or porcelain into a decorative mold.

money beads

See African trade beads.

A feldspar gemstone featuring adularescence, which describes a sheen that appears to float within a stone.

mother-of-pearl

A literal reference to the iridescent inner lining of a pearl oyster shell.

Found in Australia, it is a variety of jasper that ranges in color from pink to reddish brown and has gold and white bands

The portion of a piece of jewelry that holds a gemstone.

Italian word for the dust (usually gold) suspended in glass.

The Burmese name for high quality (translucent) jadeite.

The layers of materials secreted by mollusks that form pearls.

natural gemstone

Valuable stone that is formed by nature, without human influence.

A form of jade, appearing in darker shades of green, that was originally found and used in China.

A form of onyx that is used as a surface for engraving.

An alloy (black) that is used in engraving and is a combination of copper, lead, silver and sulphur.

In the study of light, an imaginary line perpendicular to a surface. This term is used in gemology to describe the angle at which light strikes an object.

Glass that is formed by lava that rapidly cools. Name is derived from its discovery by a Roman named Obsius.

A banded variety of quartz that ranges from translucent to opaque and appears in a color range from orange to brown which alternates with straight white bands. This gemstone is commonly dyed to create black onyx.

A gemstone that is a variety of quartz which may appear with a rainbow luster (precious opal) or reddish-orange in color (fire opal).

opalescence

Milky or pearly appearance.

The quality of not allowing the transmission of light.

optical properties

The behavior of light within a material.

organic gem

Naturally occurring substances wholly or partly derived from plants or animals. Examples are coral, jet, or pearls.

orthoclase feldspar

padre beads

See prayer beads.

Matching jewelry containing three or more pieces such as a necklace, choker, brooch, earrings, bracelet, and ring. Also see demi-parure.

Refers to jewelry made with glass that is cut to imitate faceted gemstones.

Small stones set in the surface of metal as close together as possible.

Refers to the bottom side of a gemstone.

A pearl is created when a mollusk secretes layers of calcium carbonate around an irritant that has entered its shell. When this happens by chance, the pearl is "natural." Cultured pearls are made when the irritant is intentionally placed in the shell.

Any item that is suspended from a chain or necklace.

perfumed beads

Treating beads to release a fragrance as they are warmed by the body.

A transparent stone that appears as green or olive green.

An optical effect which appears in certain gemstone materials that is often revealed by or enhanced by proper fashioning.

phosphorescence

A continuing glow exhibited by some gemstones after the source of illumination has been removed.

pietra dura

Inlaying of gold or silver into genuine tortoise shell, ivory or horn.

A soft, heavy, gray metal that can be highly polished. At times platinum has a higher value than gold.

play of color

Prismatic flashes of color seen within a gemstone.

A black variety of spinel.

prayer beads

Glass beads which are used in rosaries.

A narrow tab of metal folded over the girdle of a gemstone to secure it in a setting.

A very dark, purplish variety of garnet.

A very common mineral made of silicon dioxide which is found in any color. Varieties include: agate, amethyst, bloodstone, and a host of other gemstones.

quincite opal

See quinzite opal.

quinzite opal

Pink to reddish-colored opal.

reconstructed stone

A man-made gemstone produced by fusing together small particles of a natural stone.

Light returned to the viewer after striking a surface without entering it.

The change of velocity and resulting bending of light as it passes from one medium into another medium of different optical character.

refractometer

An instrument used to measure the degree of refraction with a gemstone. This is one of the primary tests to identify gemstone material.

White glass in a delicate, lattice (crisscrossed diagonal) pattern.

rhinestones

Artificial stones made either from crystal quartz, glass or paste that are typically designed to imitate diamonds, emeralds or rubies.

rhodochrosite

A softer stone made of carbone. It appears in a range of colors from red to off-white, typically containing curves of various color shades.

Rounded, doughnut-shaped disk.

Beads with a chevron pattern that are used in cardinals' rosaries.

Rose-shaped bead pattern which originated in Venice.

See quinzite opal.

rose quartz

A deep red quartz that, traditionally, should be reserved as a gift to one's true love.

Uncut or unfashioned gemstone material.

Tiny round beads often used as spacers or separators.

rutilated quartz

Quartz which contains yellowish crystals which range from opaque to transparent.

Glass beads made from casting powdered or pulverized glass in sand, resulting in a granular finish.

An Edwardian era, long necklace that was supplemented with a pendant or tassel.

satina bead

Bohemian glass beads with a satinlike finish.

Refers to any gemstone that is cut in the shape of a beetle.

Carved or engraved ivory or vegetable ivory. The engraved lines and textured surfaces are often colored with inks and dyes.

A pale green translucent gemstone that looks very similar to alabaster and jade. It is commonly used as a jade substitute (often fraudulently).

A mounting or the portion of a mounting that actually holds the stone.

simulated pearl

Consists of a stone nucleus surrounded by layers of plastic "nacre."

smoky quartz

A gemstone that is similar to lapis, but without shiny flecks of gold or silver.

spessartite

An orangish or reddish variety of garnet.

A mineral which resembles corundum, especially red spinel which has been mistaken for a ruby.

A mineral consisting of aluminum silicate and lithium and comes in the shape of prisms.

The ability of a gemstone to resist deterioration.

A gemstone in which the phenomenon of asterism is visible.

sterling silver

An alloy combination of roughly 90% silver and the remainder of copper and/or zinc which strengthens the silver, making it more suitable for use in jewelry and silverware.

Glass containing a high amount of lead oxide and cut to simulate a gemstone.

A substance used to imitate a more valuable gemstone. The substitute substance may be natural or man-made.

A man-made gemstone that has nearly the same physical, optical and chemical properties of a natural gemstone.

The horizontal flat surface on the crown of a facetted gemstone.

A mineral called blue zoisite that ranges from pale blue to reddish-brown. It is named after Tanzania, the country where it is mined.

Tiffany setting

A solitaire (single-stone) setting for a faceted stone consisting of six long, slender prongs.

Tiger's eye

A black quartz stone that, due to staining from iron oxide, contains yellow and golden brown stripes.

The relative lightness or darkness of a color.

A salt-like mineral (fluosilicate) of alumina. It occurs naturally in a rhomboid shape and appears in a wide range of colors, including blue, yellow (and related shades), pink, green, red, orange and others (as well as clear/colorless). It is a popular gemstone that is also a birthstone (November).

torchworked glass

See lampworked glass.

A family of gems which ranges from transparent to opaque and which exists in a very large number of colors.

translucent

A substance that allows transmitted light to clearly pass through; objects cannot be seen through a translucent substance.

transparent

A substance that allows transmitted light to clearly pass through; objects can be seen through a transparent substance.

A faceted stone with a triangular shape.

tulip setting

A prong setting with a small base that is attached to the body of the jewelry piece. It usually has a peg on the base which is inserted into a hole for solder attachment.

tumbled stone

A gem with an irregular or baroque shape.

A gemstone which name means "Turkish stone."

Abbreviation for total weight.

uranium glass

See Vaseline glass.

A very small, green-colored type of garnet that, because of its small size is rarely used, so is popular with collectors.

A type of jasper, appearing as a yellow-flecked, brown gem.

Vaseline glass

Refers to green or yellow glass that looks like Vaseline ointment and which, under ultra-violet light, glows. Also known as uranium glass since it was originally made with small amounts of uranium.

vegetable ivory

Any hard, white or cream-colored product of a plant which simulates elephant ivory. It has gained in popularity as the harvesting of animal has been banned or severely limited.

A light to medium green quartz that is created by carefully treating amethyst with heat.

Refers to gilding a silver bead.

Verneuil process

Refers to the method used to create boules. See boule.

water sapphire

A silver-colored gold caused by the presence of nickel, platinum or zinc.

white hearts

A core of white, wound glass found in the center of red eye and cranberry carnelian beads.

See African jade.

A form of obsidian that originates from California.

xalostocite

A grossular formation of pink garnet that is found within white marble. Named after Xalostoc, Mexico, its place of origin.

xyloid jasper

See jasperized wood.

Short for yttrium aluminum garnet. It is a lower luster, man-made diamond.

yellow gold

An alloy that combines copper, gold and silver.

A zinc alloy containing small amounts of aluminum and copper.

zerfass emerald

Glass dyed green to simulate emerald.

zinc spinel

Natural gemstones that, in colorless variety, are very similar in appearance to diamonds, though are much softer and are easily scratched. Also come in brown and green and, if heated, can appear in blue or golden shades.

See cubic zirconia.