Apophyllite ct.6.81

Apophyllite A popular mineral among collectors who has been recently re-considered : check http://www.mindat.org/min-283.html Is a Hydrated Potassium Calcium Sodium Silicate Fluoride Hydroxide with formula (K,Na)Ca4Si8O20(F,OH) - 8H2O . Although is quite common in natural crystal, is very difficult to cut and polish, due to his easy cleavage: a challenge for the cutters. The hardness is 4.5-5 and this gem here comes from a classic locality: Poona,India. A very small flaw is visible at naked eye Size:14.8x10.9x6.8 mm. Weight:6.81 ct. CODE#1881