corundum
1
9.9
- noun
- /kəˈrʌndəm/
- Specialized
:
corindón
- A ceramic crystalline form of corundum aluminum oxide.
Examples
-
The range is as follows: talc 1; gypsum 2; calcite 3; fluorite 4; apatite 5; orthoclase 6; quartz 7; topaz 8; corundum 9; and diamond 10.
Academic text (1993) -
His own colony's deposit only produced the paler corundum, rarely a fine gem.
Fiction book (1998) -
Suddenly I'm lying on the corundum, watching Tannie shrink away, vanishing even before she strikes the pond.
Fiction book (2000) -
A friend of Rod's, the corundum miner Diorite, searches the crash site for survivors.
Fiction book (1998) -
Meanwhile, the older children were coming home from the gravel pit with carts full of corundum and occasional gem-quality stones.
Fiction book (1998) -
So I describe it as an accident, another misstep from the high corundum mesh, and maybe we should repair those railings during the next down cycle.
Fiction book (2000) -
Haemum and Chae rose early to go uphill and dig gravel out of the mine, an old stream bed rich in corundum.
Fiction book (1998) -
She seems to be waiting for me, rocking nervously back and forth, the corundum mesh leaving its mark on her thin rump.
Fiction book (2000) -
Then, with practiced haste, we begin to climb the bright blue corundum stairs, zigzagging up and up as the second and final klaxon roars, warning us that the janitors are being released from their bunkers.
Fiction book (2000) -
The jeweler carefully polished the corundum to reveal its stunning ruby color.
Synonyms
1
8.9
A hard white material used to make ceramics, glass and aluminum
1
5.0
A hard white material made from aluminum and oxygen used for tools and coatings
A very hard mineral used for cutting and grinding and as gems like ruby and sapphire
How Hard
Surface Forms
Etymology
The word corundum probably comes from an old South Asian word for 'ruby' that travelled into Arabic and then Latin before English. Since both ruby and sapphire are types of corundum, the name now means this very hard mineral used for gems and for grinding or polishing.