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corundum

[ kuh-ruhn-duhm ]
/ kəˈrʌn dəm /
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noun

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.

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Origin of corundum

1720–30; <Tamil kuruntam; akin to Sanskrit kuruvinda ruby
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2021

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British Dictionary definitions for corundum

corundum
/ (kəˈrʌndəm) /

noun

a white, grey, blue, green, red, yellow, or brown mineral, found in metamorphosed shales and limestones, in veins, and in some igneous rocks. It is used as an abrasive and as gemstone; the red variety is ruby, the blue is sapphire. Composition: aluminium oxide. Formula: Al 2 O 3 . Crystal structure: hexagonal (rhombohedral)

Word Origin for corundum

C18: from Tamil kuruntam; related to Sanskrit kuruvinda ruby
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Scientific definitions for corundum

corundum
[ kə-rŭndəm ]

An extremely hard mineral occurring in many colors, either as shapeless grains or as rhombohedral crystals. It also occurs in gem varieties such as ruby and sapphire and in a dark-colored variety that is used for polishing and scraping. Corundum is found in igneous and carbonate rocks. Chemical formula: Al2O3.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
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