corundum

== English == === Etymology === From Tamil குருந்தம் (kuruntam, “ruby, sapphire”) First attested in the early 18th century. === Pronunciation === (UK, US) IPA(key): /kəˈɹʌn.dəm/ === Noun === corundum (countable and uncountable, plural corundums) (mineralogy) An extremely hard mineral, a form of aluminum oxide with the chemical formula Al2O3, that occurs in the form of the gemstones sapphire and ruby; it is used as an abrasive. ==== Derived terms ==== ==== Translations ==== === Further reading === David Barthelmy (1997–2026), “Corundum”, in Webmineral Mineralogy Database. “corundum”, in Mindat.org, Keswick, Va.: Hudson Institute of Mineralogy, 2000–2026.