Ruby

Ruby, or RED SAPPHIRE, one of the most valuable of gems, is the red, translucent variety of crystalline alumina. It is found chiefly in Burmah, where the mines are now worked by an English company. This stone is often termed the Oriental ruby, the best colour being known as pigeon's-blood. The orqinary ruby of lapidaries and watchmakers is red spinel (MgOA1₂0₂), crystallising in the Cubic system. It is also called the spinel ruby; when rose-red, the balas ruby; when orange-red, the rubicelle; or when violet, almandine ruby. [SPINEL.]