corundum

[ kuh-ruhn-duh m ]
/ kəˈrʌn dəm /

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.

Origin of corundum

1720–30; < Tamil kuruntam; akin to Sanskrit kuruvinda ruby

Example sentences from the Web for corundum

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

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.