C. 1990 Vintage 9.62 ct. t.w. Mixed-Stone and Black Onyx Bird Pin in 18kt Yellow 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.

YELLOW GOLD: Gold is a precious metal with a natural yellow color. It is quite soft and often alloyed with other metals to increase its strength. The purity of the metal is indicated by a unit called a "karat," with 24kt having the highest percentage of natural gold.

REVOLVER: A safety that conceals the point of a pin and keeps it in place with a revolving lever mechanism.

EMERALD: the birthstone of May, and from the beryl mineral family, the emerald has been a prized possession of royalty since ancient times and a good quality emerald can be as or even more expensive than a fine diamond of the same carat. Emeralds are considered the traditional gift for the 55th wedding anniversary.

SAPPHIRE: A favorite gemstone of ancient priests and royalty, the sapphire radiates sophistication and grace. This prized gem comes in every hue of blue, plus the more unexpected shades of pink, yellow, green and orange, and is September's birthstone.

RUBY: A bold fiery stone, the ruby is a symbol of wealth, vitality and love. When cut and polished, the ruby's high luster is as dazzling as a diamond's. Ruby jewelry makes the perfect gift for loved ones and is the birthstone for July.

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.

FREE-FORM: Any gemstone with an irregular shape.