pyrobitumens
Pyrobitumen is a term used to describe solid, amorphous, carbonaceous materials that are formed by the thermal alteration of organic matter, typically sedimentary rocks. These materials are characterized by their insolubility in common organic solvents and their high carbon content. Pyrobitumen is not a mineral in the strict sense, but rather a type of residue.
The formation of pyrobitumen is a result of natural processes, primarily the heating of hydrocarbon-rich source
Pyrobitumens can range in appearance from dull black to shiny and vitreous. Their hardness and brittleness