Spinel

Spinels come in a wide variety of colors, including red. Although rubies and spinels are now identified gemologically as two distinct gem species, some stones historically classed as rubies have actually proven to be spinels. However, at first glance, a red spinel can still be confused with a ruby. Red spinel on calcite, Mogok Valley, Mogok Township, Pyin-Oo-Lwin District, Mandalay Division, Myanmar. Photo by Géry Parent. Licensed under CC By-ND 2.0.

Article: An Introduction to Gem Identification

Credit: Géry Parent