1. Noun
A stone imagined by some to be of impenetrable hardness; a name given to the diamond and other substances of extreme hardness; but in modern mineralogy it has no technical signification. It is now a rhetorical or poetical name for the embodiment of impenetrable hardness.
2. Noun
Lodestone; magnet.
3. Noun
very hard native crystalline carbon valued as a gem
Vocabulary classified under Chemistry
More about this word
Synonyms and related words
Explore this word