Monday, November 17, 2008

Paraiba Tourmaline

Paraiba Tourmaline

This tourmaline has been a very controversial gemstone. The colour is of a cyan colour, greenish blue (or clear ocean blue). Under absorption spectrum, it has a copper absorption band.

Sunday, November 2, 2008

Interesting Facts

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.