APA (7th ed.) Citation

Holden, M., & Mathez, E. A. (1991). The encyclopedia of gemstones and minerals. Facts on File.

Chicago Style (17th ed.) Citation

Holden, Martin, and Edmond A. Mathez. The Encyclopedia of Gemstones and Minerals. New York: Facts on File, 1991.

MLA (9th ed.) Citation

Holden, Martin, and Edmond A. Mathez. The Encyclopedia of Gemstones and Minerals. Facts on File, 1991.

Warning: These citations may not always be 100% accurate.