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.

STERLING SILVER: Also known as "Standard Silver," sterling silver is silver alloyed with other metals to increase the hardness and durability. Generally, sterling is 92.5% silver and 7.5% other metals. Some sterling silver jewelry is plated with 14kt-18kt gold and referred to as "vermeil," or "gold over sterling."

QUARTZ: From the icy shimmer of rock crystal quartz to the delicate pink of rose quartz to the moody hues of smoky quartz, this gemstone offers something for everyone. Quartz, found in endless colors and varieties, is a popular choice for bracelets, necklaces, rings and earrings.

OVAL: An elliptical shape that resembles an egg.

CITRINE: A member of the quartz family, citrine symbolizes cheerfulness and prosperity. Its name is derived from the French word citron meaning lemon. This sunny stone comes in colors from lemon yellow to amber brown, with its coloring agent attributed to iron. Citrine is the birthstone for November.

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 I-J: Near-colorless