C. 1980 Vintage 2.50 Carat Emerald and .10 Carat Diamond Necklace with Green Enamel in 18kt Yellow Gold. 17"

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.

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.

OVAL: An elliptical shape that resembles an egg.

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.

BRILLIANT: A gemstone cut to enhance brilliance without sacrificing much carat weight. Typically has 58 facets.

CLARITY SI1: Slightly Included. Inclusions are noticeable under 10x magnification.