Feature Gems & Gemology, Winter 1999, Volume 35, No. 4

Garnets from Madagascar with a Color Change of Blue-Green to Purple

Gemological, chemical, spectroscopic, and microscopic properties of blue-green color-change garnets from a new deposit near Bekily, Madagascar, are given. The samples are members of the pyrope-spessartine solid-solution series, with smaller constituents of almandine and grossular. The alexandrite-like color change from blue-green in daylight to purple in incandescent light is mainly caused by relatively high amounts of vanadium (about 1 wt. % V2O3). These garnets are particularly noteworthy because they represent the first commercially available “blue” garnets.