shungite

Etymology
First described from a deposit near Shunga village in Karelia, Russia,.

Noun

 * 1)  A black, lustrous, non-crystalline mineraloid consisting mostly of carbon, used as a pigment in art and an antibacterial water treatment.

Usage notes

 * The term shungite was originally used in 1879 to describe a mineraloid with more than 98% carbon. More recently the term has also been used to describe shungite-bearing rocks, leading to some confusion.