» Mon Sep 26, 2011 11:51 am
Interesting, it's a real mineral.
Corundum is a crystalline form of aluminium oxide with traces of iron, titanium and chromium. It is a rock-forming mineral. It is one of the naturally clear transparent materials, but can have different colors when impurities are present. Transparent specimens are used as gems, called ruby if red and padparadscha if a pink-orange, while all other colors are called sapphire. The name "corundum" is derived from the Tamil word "kuruntam" meaning "ruby", and related to Sanskrit "kuruvinda". Because of corundum's hardness it can scratch almost every other mineral.