Also 8 corivindum, -vendum, coriundum, 9 corundon. [a. Tamil kurundam, in Telugu kuruvindam, Hindī kurunḍ; Skr. kuruvinda ‘ruby.’ Cf. also CORINDON.]
1. A crystallized mineral belonging to the same species as the sapphire and ruby, but opaque or merely translucent, and varying in color from light blue to smoky grey, brown and black; called also Adamantine Spar.
a. 1728. Woodward, Catal. For. Fossils, 6. Nella Corivindum is found in fields where the rice grows.
1798. Greville, in Phil. Trans., LXXXVIII. 403. My friend Colonel Cathcart sent me its native name, Corundum, from India, with some specimens … in 1784.
1794. Kirwan, Min., I. 335. The second, in India, near Bombay and there called corundum.
1868. Dana, Min., 138. Corundum … is ground and used as a polishing material, which, being purer, is superior in this respect to emery. It was thus employed in ancient times.
1886. Pall Mall Gaz., 9 March, 11/2. A new process for obtaining pure aluminium from aluminium oxide or broken corundum.
2. Min. Used as the name of a mineral species, under which Dana includes the transparent sapphire (including the ruby, and the (so-called) oriental amethyst, emerald and topaz), the opaque or translucent adamantine spar (= prec. sense), and the granular emery. It consists of crystallized alumina (Al2 O3) variously colored.
1804. Phil. Trans., XCIV. 44. Those stones which offer the greatest resistance to a mechanical division, such as quartz, Blue corundum or sapphire.
1868. Dana, Min., 139. Emery … in which the corundum is in distinct crystals.
1870. H. Macmillan, Bible Teach., xiv. 273. The sapphire … the ruby and the Oriental topaz … are all mere coloured varieties of the mineral substance known as corundum.
3. attrib., as in corundum point, stick, tool, wheel, used in polishing, dressing millstones, etc.
1792. Oakley, in Phil. Trans., LXXXVIII. 407. Among these broken lumps, the Corundum stone is found.
1873. J. Richards, Wood-working Factories, 106. Corundum or emery wheels are now generally used for dressing both saws and cutters.
1884. F. J. Britten, Watch & Clockm., 86. The edges of holes in dials may be trimmed with corundum sticks.
