A transparent red corundum valued according to shade of color. Large rubies are often worth more than fine diamonds of the same size. Darker rubies come from Thailand. Rubies also occur in Sri Lanka, Afghanistan, and North Carolina. A transparent corundum, or aluminum oxide.
Sapphires range from white through blue, violet, yellow, and green to near black.
Blue star sapphires with six rays are favorite stones. Fine sapphires are equal in value to diamonds of equal size. Found in Myanmar, Thailand, Sri Lanka, and Jammu and Kashmir. A variety of onyx with parallel layers of white, brown, black, and red sard. Used in cameos and intaglios.