C. 1930 Vintage 5.38 Carat Emerald Necklace With Diamonds and Black Onyx in Platinum and 18kt Gold. 16.25"

PLATINUM: A rare precious metal cherished for its longevity and strength. Platinum is naturally white, durable, dense, and resilient to discoloration. Most platinum in jewelry is at least 95% pure since it does not require alloys or plating.

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.

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.

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 H-I: Near-colorless

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

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.

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.