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Ruby gem.JPG
A ruby gemstone
Category Corundum variety, Oxide mineral
(repeating unit)
aluminium oxide with chromium, Al2O3
Color Red shades
Luster Vitreous
References [1]

A ruby is a kind of precious stone. It is often associated with emerald, sapphire and topaz.[1] It is usually red, but can sometimes be other colors.[1] It is formed of aluminum and oxygen (Al2O3)[1], and that means it's a kind of corundum. A small amount of chromium makes the color.

Natural rubies

References[change | change source]

  1. 1.0 1.1 1.2 1.3 "Ruby at Mindat". Retrieved 23 August 2013.