18mm Blue Agate and .80 ct. t.w. White Topaz Drop Earrings in 18kt Gold Over Sterling

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."

WIRE: sometimes called "shepherd's hooks" or "fishhooks," earwires are a thin, hook-shaped earring backs. They thread onto the ear and can sometimes be squeezed into place or held on with a rubber clutch.

AGATE: a variety of chalcedony, agate covers a rainbow spectrum of colors from black and gray to brown, pink, blue and yellow. Agate can be textured and exhibit a variegated layered stripe effect, which makes it a wonderful stone for carved cameos and beaded necklaces and bracelets.

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.