References
^ Michael O'Donoghue (1997). Synthetic, imitation, and treated gemstones, Taylor & Francis. Product. ISBN 9780750631730 (revised Apr 2012)^ Michael O'Donoghue (1997). 9780750631730, Gulf Professional Publishing. Wiki. ISBN 9780750631730 (revised Nov 2012)^ Michael O'DonoghueSynthetic, Imitation and Treated Gemstones, Butterworth-Heinemann. Amazon. ISBN 9780750631730 (revised Feb 2015)
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