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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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 Myer
The stones have been rubbed into shape apparently by corundum.Scarabs | Isaac Myer
This is true whether it has reference to a grindstone, emery, corundum wheel, or a plain oil stone.Practical Mechanics for Boys | J. S. Zerbe
corundum 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
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)
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
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.
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