1. Light blue topaz(those natural ones) looks like Aquamarine BUT it has a better Lustre due to the RI difference. Topaz has an RI of 1.61 - 1.63, Aquamarine has an RI of 1.57 - 1.58. Topaz is harder too (Moh's Scale of Hardness = 8, Aquamarine = 7-7.5).
2. Topaz has this liquid inclusion that looks likea viscous solution.
3. Topaz has a Trigonal crystal system.
Huiying and I just sat for the Gem Idendification Advanced Exam at Far East Gemological Institute yesterday. It was tiring but ok.
I spent the last 4 days trying to identify 20 stones. It was really fun when you could tell the difference between Synthetics and naturals. But I guess it really takes a lot of experience and knowledge.
Sunday, November 2, 2008
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