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Color enhancement of Australian natural sapphire by the hydyothermal method  

Kim, Hee-Seung (Department of Gemological Engineering, Graduate School, Dongshin University)
Publication Information
Journal of the Korean Crystal Growth and Crystal Technology / v.16, no.6, 2006 , pp. 240-243 More about this Journal
Abstract
The significant color enhancement in low quality Australian natural sapphire has been achieved by a hydrothermal method. The optimal conditions for the color enhancement of Australian natural sapphire were as follows; hydrothermal reaction temperature: $320{\sim}350^{\circ}C$, duration : 3 days, hydrothermal solvent: 2 M NaOH solution. After the hydrothermal treatment, Australian natural sapphires of transparent colors were obtained, and their grades were found to be improved from commercial to middle/top grade by value chart analysis.
Keywords
Hydrothermal method; Australian natural sapphire; Color enhancement;
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