C. 1940 Vintage Black Agate Cameo Drop Earrings in 14kt Yellow Gold and 18kt Yellow Gold

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.

LEVER: An earring backing with a hook-shaped insert and a hinged leverback to hold it in place.

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.

OVAL: An elliptical shape that resembles an egg.

CARVED: When a gemstone is cut so that the outline or surface takes the form or likeness of a specific image or pattern.