Thursday, 10 November 2016

Blue Garnet

Garnets are a group of silicate minerals that have been used since the Bronze Age as gemstones and abrasives. All garnets possess similar physical properties and crystal forms, but differ in chemical composition. The different species are pyrope, almandine, spessartine, grossular, uvarovite and andradite.

Garnet is available in a plethora of colours and is found around the world. Rarest and most valuable are blue garnets. They were discovered in 1998 in Bekily, Southern Madagascar. They are actually colour change garnets, appearing blue under fluorescent light changing to reddish-purple under incandescent light. The color change is pronounced and these rare garnets have become highly sought after by collectors.
Color change garnets are due in part to varying concentrations of vanadium and chromium. The blue-green to purple color change garnets have relatively high concentrations of vanadium and low concentrations of chromium.

Very fine, gem quality blue garnets over 10 carats are scarce and valuable.