Green Chalcedony Scrolled Ring with Black Spinel and White Topaz in 18kt Gold Over Sterling. Size 7

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."

CHALCEDONY: a family of minerals that is often milky gray or bluish in color. Chalcedony includes a number of stones including onyx (black), carnelian (waxy red), agate (wide ranging palette) and bloodstone (brownish red.)

OVAL: An elliptical shape that resembles an egg.

CHECKERBOARD: A technique that creates a contrast of dark and light when light hits the pattern of square or diamond-shaped facets.

TOPAZ: Available in a stunning selection of shades, the topaz's sky blue hue is one of the most popular colors for jewelry designs. Once thought to offer protection, today topaz is favored for its durability and affordability. Yellow topaz is the birthstone for November while blue topaz is for December.

SPINEL: This rare and durable gemstone, found in a beguiling shade of inky black, catches the eye when set in rings, bracelets, necklaces and earrings. Spinel is also found in captivating tones of pink, purple and green. The red variety is beautiful in its own right and in ages past it was mistaken for a ruby.