James E. Shigley and Carol M. Stockton, March 1, 1984
Similarities between natural spinels - with intense blue colour - and synthetic material, have led to difficulties in the recognition of the natural stones by traditional methods.
Read MoreSam Muhlmeister, John I. Koivula, June 1, 1993
Examination of red and blue samples of a relatively new flux synthetic spinel from Russia established criteria by which they can be separated from their natural counterparts.
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