Chalcedony (pronounced kahl-sid-nee) is the form of quartz that is compact and microcrystalline. It occurs in many different forms, colors, and patterns, and many varieties have been used as gemstones. In the gem trade, the term chalcedony is often used specifically to describe the white, gray, or blue translucent type of chalcedony, but its technical term includes all additional varieties. Some varieties of chalcedony include Agate, Aventurine, Bloodstone, Carnelian, Chrysoprase, Jasper, Onyx, and Tiger’s Eye. The term chalcedony is used to distinguish the translucent stones from varieties of agate that are multicolored and banded.