Difference between revisions of "Corundum"
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| − | '''Corundum''' is | + | '''Corundum''' is a very hard mineral - [[Moh's hardness scale]] of 9, second only to a [[diamond]]. When comparing absolute hardness, a diamond is four times harder than corundum.<ref>http://www.galleries.com/minerals/hardness.htm</ref> A clear and colorless synthetic corundum is often used for watch crystals to resist scratching as it can only be scratched by another corundum surface or a diamond. |
| − | + | Corundum is an aluminum oxide. In perfect form, corundum is clear though various impurities will change the color of the mineral. When colored red, corundum is called a [[ruby]]. Other clear and translucent forms of corundum are called [[sapphire]]s. | |
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| + | == References == | ||
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[[category:Geology]] | [[category:Geology]] | ||
[[Category:Minerals]] | [[Category:Minerals]] | ||
[[Category:gems]] | [[Category:gems]] | ||
Revision as of 22:28, September 13, 2007
Corundum is a very hard mineral - Moh's hardness scale of 9, second only to a diamond. When comparing absolute hardness, a diamond is four times harder than corundum.[1] A clear and colorless synthetic corundum is often used for watch crystals to resist scratching as it can only be scratched by another corundum surface or a diamond.
Corundum is an aluminum oxide. In perfect form, corundum is clear though various impurities will change the color of the mineral. When colored red, corundum is called a ruby. Other clear and translucent forms of corundum are called sapphires.