| 1 | Erickson, J.,2000. An Introduction to Fossils and Minerals, Revised Edition, Facts On File Inc. Publishing, New York, 288 p. |
| 2 | Schumann, W., 2009. Gemstones of the World: Newly Revised & Expanded Fourth Edition (Hardcover), Sterling Publishing, 272 p. |
| 3 | O?Donoghue, M., 2006. Gems, Sixth Edition (Hardcover), Butterworth-Heinemann publishing, 936 p. |
| 4 | Yeniyol, M., 2004. Mineraloji, 324 s. |
| 5 | Wenk, H.R., Bulakh, A.G., 2004. Minerals: Their Constitution and Origin,Cambridge, 650 p. |