White (Clear) Topaz Cabochon

Refraction Index: 1.610 - 1.620
Hardness:  8
Specific Gravity:  3.53 to 3.56
Dispersion: 0.014
Treatment: None

Metal Clay, safe to fire.
Test results; Silver 1200F-1HR-OK, Silver 1475F-1HR-OK, Silver 1650F-2HR OK,  Bronze 1525F-2HR-OK, Copper 1778F-30min-OK