C. 1980 Vintage 1.25 ct. t.w. Aquamarine Leaf Pendant Necklace with Diamond Accent in 14kt Yellow Gold. 18"

14KT: Karat (abbreviated kt or K) is a unit that indicates the purity of gold in the metal. 14kt is 58.33% gold. In the United States, 14K 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.

CABLE: One of the most popular and classic of chain styles, created from interlocking oval links unvarying in size.

LOBSTER CLASP: named after the pinching style of the hook, this clasp is often shaped like a lobster's claw. Use your finger to work the lever to open the clasp.

FIXED: A bale that is worked into the actual design of a pendant. Typically seen in slide pendants.

AQUAMARINE: The birthstone of March, harbinger of spring, aquamarine's powers of revelation are legendary. Usually cut as a brilliant or a step cut, and a member of the beryl family, aquamarine can be found in a range of pale blue hues and aqua green colors.

MARQUISE: An elliptical shape that comes to a point at the top and bottom. Sometimes referred to as a "navette."

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.