Thanks again, of troy, for the explanation there.

Actually, when you think about it, it does make sense that something as hard as anthracite would/could glitter very much since diamonds do glitter with unmatched refulgence. Which makes me wonder, is the glittering of the diamond unmatched? And what would be the term to describe 'glittering'? We have the mohs scale and the Richter scale and all other kinds of scales, but do we have a glittering scale?