Corundum

Corundum
Corundum Co*run"dum (k[-o]*r[u^]n"d[u^]m), n.; pl. {Corundums} (k[-o]*r[u^]n"d[u^]mz). [Also corindon.] [From Hind. kurand corundum stone.] (Min.) The mineral alumina ({Al2O3}), as found native in a crystalline state. Transparent varieties are used as gemstones, including {sapphire}, which is the fine blue variety; the {oriental ruby}, or red sapphire; the {oriental amethyst}, or purple sapphire; and {adamantine spar}, the hair-brown variety. It is the hardest substance found native, next to the diamond. [1913 Webster +PJC]

Note: The name corundum is sometimes restricted to the non-transparent or coarser kinds. {Emery} is a dark-colored granular variety, usually admixed with magnetic iron ore. [1913 Webster]


The Collaborative International Dictionary of English. 2000.

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  • corundum — /keuh run deuhm/, n. a common mineral, aluminum oxide, Al2O3, notable for its hardness: transparent varieties, as sapphire and ruby, are used as gems, other varieties as abrasives: often made synthetically. [1720 30; < Tamil kuruntam; akin to Skt …   Universalium

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  • corundum — noun Etymology: Tamil kuruntam; akin to Sanskrit kuruvinda ruby Date: 1804 a very hard mineral that consists of aluminum oxide occurring in massive and crystalline forms, that can be synthesized, and that is used for gemstones (as ruby and… …   New Collegiate Dictionary

  • corundum — noun an extremely hard mineral, a form of aluminium oxide with the chemical formula AlO, that occurs in the form of the gemstones ruby and sapphire; it is used as an abrasive …   Wiktionary

  • corundum — Native crystalline aluminum oxide. [Hind. kurand] * * * co·run·dum kə rən dəm n a very hard mineral Al2O3 that consists of alumina occurring in massive form and as variously colored crystals which include the ruby and sapphire * * * co·run·dum… …   Medical dictionary

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