Diamonds in the rough
Diamonds in the rough, note the regular octahedral forms and trigons (of positive and negative relief) formed by natural chemical etching. Photo credit: Wikimedia.

Minerals

What are diamonds?

Diamonds are formed from pure carbon, one of the most abundant elements on planet Earth. Diamonds, even from ancient times, have been sought for their extraordinary hardness (they are the hardest substance known) and their brilliance, especially in the colorless transparent gemstone variety. Ironically the other form of pure carbon…