face=Verdana color=#000099 size=2>CONFETTI LUCITE face=Verdana size=2>
Confetti lucite is transparent plastic with glitter or other small pieces of material within it. Whimsical bangles, earrings, pins, necklaces and other jewelry have been made from confetti lucite.

COPPER
Copper is a soft metal often used in jewelry. It is used in making bronze, brass, and gold alloys. The enameled copper leaf pin above is marked Matisse, from the "Renoir of California" jewelry company.

CORAL face=Verdana size=2>
Coral is an animal that grows in colonies in the ocean. Coral polyps secrete a strong calcium structure that is used in jewelry making. Coral ranges in color from pale pink (called angelskin coral) to orange to red to white to black. The most valued colors are deep red (called noble coral) and pink. In jewelry making, coral is either carved into beads, cameos, or other forms, or is left in its natural branch-like form and just polished. It used to be thought that coral protected the wearer, so it was a traditional gift to children. Coral has a hardness of about 3.5 and a specific gravity of 2.6 to 2.7. Since it is composed of calcium carbonate, coral will effervesce if touched with acid. Imitation coral is made from glass, porcelain, or plastic.

CORONET SETTING
A coronet setting (also called ch?ton or arcade setting) is one in which the stone is held in by many metal claws around a metal ring.

CORUNDUM
Corundum is a very hard mineral (hardness 9); only diamond is harder. Corundum is called ruby or sapphire, depending on the color (which depends on which metallic oxides are present). In its rare pure form, corundum is colorless and called white sapphire. Rubies contain chromic oxide, blue sapphires contain titanium, yellow sapphires contain ferric oxide. Other impure forms are opaque. Corundum stones can produce beautiful asterisms. The word corundum comes from the Tamil word for ruby. Corundum has a specific gravity of 3.96-4.01.

CRIMP BEAD
A crimp bead is a soft, metal bead through which string (for a bracelet or necklace) is threaded; the crimp bead can be squeezed shut with a pliers to secure the end loops of the threading material fasteners onto the clasps.

CROWN
The crown is the upper part of a gemstone.

CROWN GLASS
Crown glass is glass that contains no lead oxide. Some fake rhinestones are made from crown glass.

CRYSTAL (GLASS)
Crystal is high-quality glass containing at least 10% lead oxide. Lead added to the melt produces very clear glass resembling rock crystal. The process of making lead crystal was discovered by the English glassmaker George Ravenscroft in 1676. Crystal is colored by adding various metallic oxides to the melt.

CRYSTAL (NATURAL)
A crystal is a solid whose atoms form a very regular structure. Some crystals include quartz, diamond, and emerald.

CRYSTAL HABIT
Crystal habit is the crystal form that a particular crystal has. The most common crystal habits:

Prismatic - elongated with parallel sides, like emerald, tourmaline
Tabular - short and flat (table-like), like morganite
Ocatahedral - eight faces, like diamond
Dodecahedral - 12 faces, like garnet
Acicular - needle-shaped, like rutilated quartz
Platy - occurring in very thin plates, like hematite

face=Verdana color=#000099 size=2>CUBIC ZIRCONIUM face=Verdana size=2>
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. The gold-toned, hinged cuff above is by the jewelry designer Miriam Haskell.

CUFFLINKS
Cufflinks are men's jewelry that close the buttonholes of the cuff of a long-sleeved shirt. Some cufflinks are basically two button-like objects connected by a chain; the bottons go through the cufff's buttonholes. Another type of cufflink has a decorative button attached to a stick whose end swivels out to form a T-shape that goes through the buttonhole. Cufflinks were first worn in the 1800's.

CULET face=Verdana size=2>
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.

CULLINAN DIAMOND
The Cullinan diamond (also called the Star of Africa) is the largest diamond yet found, weighing 3,106 carats (roughly 1.3 pounds) in its rough form. It was mined at the Premier Mine in South Africa in 1905. This enormous gem was named for the chairman of the company that owned the mine. It was given to King Edward VII of England for his birthday in 1907. The diamond was cut (by Joseph J. Asscher of Amsterdam) into many stones, including the Cullinan I (530 carats, pendelique-brilliant shaped, the largest cut diamond in the world), the Cullinan II (317 carats, cushion shaped), Cullinan III (94 carats, pendelique shaped), Cullinan IV (63 carats, square-brilliant shaped), and many other smaller stones.

CULTURED PEARL
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.

CUT BEADS
Cut beads are glass beads that have been faceted. This process makes the bead reflect and refract more light.

CUT STONES
Common cuts include the brilliant cut, old European cut, emerald cut, radiant cut, rose cut, step cut, pendelique cut. Mixed cuts in which the style of the facets above and below the girdle are different. Other, more unusual cuts, are know as fantasy cuts (like the heart cut).