C. 1990 Vintage Black Agate, Black Onyx and Mother-of-Pearl Cameo Pin/Pendant in 18kt White Gold

18KT: Karat (abbreviated kt or K) is a unit that indicates the purity of gold in the metal. 18kt is 75% gold. In Europe, 18K yellow gold is most favored and used in jewelry.

WHITE GOLD: Gold is a precious metal which is naturally quite soft. To give it a white color and increase its strength, gold is alloyed with white metals, such as silver and/or palladium, and often plated with rhodium. The purity of the metal is indicated by a unit called a "karat," with 24kt having the highest percentage of natural gold.

PUSH-PULL: Seen mostly on estate pins, a push-pull safety is a tube-like mechanism that slides over the end of the pin to secure it.

HINGED: A bale with a hinge. The hinge allows the pendant to be placed on and taken off a chain easily and without sliding. Ideal for putting pendants on chains that have large clasps.

AGATE: a variety of chalcedony, agate covers a rainbow spectrum of colors from black and gray to brown, pink, blue and yellow. Agate can be textured and exhibit a variegated layered stripe effect, which makes it a wonderful stone for carved cameos and beaded necklaces and bracelets.

OVAL: An elliptical shape that resembles an egg.

CARVED: When a gemstone is cut so that the outline or surface takes the form or likeness of a specific image or pattern.

MOTHER-OF-PEARL: Glowing with an iridescent beauty, mother-of-pearl has been showcased in jewelry designs for thousands of years. As mother-of-pearl is a natural substance, it may vary in appearance, and its distinctive shimmer lends a quiet elegance to fine jewelry.

ONYX: A favorite of the ancient Greeks and Romans, this gemstone adds a sophisticated shine to rings, necklaces, bracelets and earrings. A dyed form of chalcedony, onyx is most popularly found in black although it can be green, white or red, as well.