noun
corundum
kuh-RUN-dum/kəˈrʌndəm/
A very hard crystalline mineral made of aluminum oxide.
Corundum is hard enough to scratch most other common minerals.
Etymology
Tamil kurundam named ruby and sapphire, connecting the mineral's name with gemstones rather than its chemical composition. Its deeper origin is unknown; the English term denotes the very hard aluminum-oxide mineral.
In context
and Polished into a gemstone at Jeb blackwat asks question what's the difference between rubies emeralds sapphires Etc rubies and sapphires are the same exact mineral the mineral is called corundum and it is made up of aluminum and oxygen
More examples
- Ruby and sapphire are varieties of corundum.
- Manufacturers use corundum as an abrasive in grinding tools.
- The geologist tests the crystal's hardness to help identify it as corundum.
Forms
corundum
Similar words
- alumina
- Names aluminum oxide generally, rather than this specific mineral.