corundum
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.
Origin of corundum
1Words Nearby corundum
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
How to use corundum in a sentence
Pliny says, corundum was used in the form of a splinter fixed in an iron style.
Scarabs | Isaac MyerThe stones have been rubbed into shape apparently by corundum.
Scarabs | Isaac MyerThis is true whether it has reference to a grindstone, emery, corundum wheel, or a plain oil stone.
Practical Mechanics for Boys | J. S. Zerbecorundum and pure emery are ores that are very rich in aluminum, containing about fifty-four per cent.
corundum is the hardest substance known, next to the diamond.
The A B C of Mining | Charles A. Bramble
British Dictionary definitions for corundum
/ (kəˈrʌndəm) /
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)
Origin of corundum
1Collins 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
[ kə-rŭn′dəm ]
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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