C. 1980 Vintage .65 ct. t.w. Diamond and .10 Carat Ruby Seahorse Pin with Green Enamel 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.

Diamond: The hardest and most brilliant of all gemstones, a diamond can make the heart race with its pure and fiery spark. An ancient symbol of love, a diamond is the preferred gemstone for tokens of affection, such as rings, earrings, necklaces and bracelets. Diamond is the birthstone for April.

SINGLE-CUT: A gemstone cutting technique that dates back to the 1300s. Still used today, the single-cut usually features 18 facets that go in one direction without crossing each other.

Color Grade H-I: Near-colorless

Clarity VS1-VS2: Very slightly included. Inclusions are observed with effort under 10x magnification, but can be characterized as minor.

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.

CABOCHON: A style of cutting gemstones to achieve a smooth, domed surface with an absence of facets.