C. 1970 Vintage 2.00 Carat Ruby and 1.05 Carat Sapphire Necklace with Diamonds in 18kt Two-Tone Gold. 15.5"

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.

TWO-TONE GOLD: Gold is a precious metal which is often alloyed with other metals to increase strength and create different colors. A two-tone gold piece includes two colors of gold: yellow, rose, white, or gunmetal-finished gold. The purity of the metal is indicated by a unit called a "karat," with 24kt having the highest percentage of natural gold.

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.

Color Grade G-H: Near-colorless

CLARITY SI1-SI2: Slightly Included. Inclusions are noticeable under 10x magnification.

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.

OVAL: An elliptical shape that resembles an egg.

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

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.