Abelsonite

Abelsonite (nickel porphyrin) is a mineral that can be pinkish-brown, purple, or reddish-brown in color and is formed from porphyrin crystals. It is platy (made in plates like mica) and fragile.

Porphyrins are organic ring compounds like haeme, the pigment in red blood cells.

It is found in the Green River Formation of Utah, in the United States.