GEMS Cipriani, Curzio Simon & Schuster’s guide to gems & precious stones. Simon & Schuster, 1986
GEMS Desautels, Paul E. Gems in the Smithsonian. Smithsonian Institution Press, 1972
GEMS Desautels, Paul E. The gem kingdom. Random House, 1970
GEMS Greenbaum, Walter W. The gemstone identifier. Prentice-Hall, 1988