Blue star sapphires with six rays are favourite 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.
Chief sources are Brazil, Uruguay, Madagascar, India, and Texas.
A red, violet, blue, green, or yellow magnesium aluminate. Found in Myanmar, Thailand, and Sri Lanka. A reddish feldspar with fiery reflections. An aluminium fluosilicate occurring in tawny yellow, blue, green, reddish violet, pink, and colourless varieties. Found in Brazil, Siberia, Sri Lanka, and the United States.