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4. Color Encyclopedia of Gemstones;Arem,1987
5. S. Saeseaw, W. Wang, K. Scarratt, J.L. Emmett, T.R. Douthit, “Distinguishing heated spinels from unheated natural spinels and from synthetic spinels”, [cited 19 Sep 2014], available online: http://www.giathai.net/distinguishing-heated-spinels/