(n.) The earth alumina, as found native in a crystalline state, including sapphire, which is the fine blue variety; the oriental ruby or red sapphire; the oriental amethyst or purple sapphire; and adamantine spar, the hair-brown variety. It is the hardest substance found native, next to the diamond.
Webster's Revised Unabridged Dictionary
| APA | Webster's. (2011). corundum. Retrieved September 23, 2026, from http://smartdefine.org/corundum/definitions/1991939 |
| Chicago | Webster's. 2011. "corundum" http://smartdefine.org/corundum/definitions/1991939 (accessed September 23, 2026). |
| Harvard | Webster's 2011, corundum, Smart Define, viewed 23 September, 2026, <http://smartdefine.org/corundum/definitions/1991939>. |
| MLA | Webster's. "corundum" 27 May 2011. Web. 23 September 2026. <http://smartdefine.org/corundum/definitions/1991939> |