Pyrolusite

Name:
Pyrolusite
Detailed information:

Chemistry name:	manganese dioxide, black
M Formula:	MnO2
Properties:
Iron-black to dark steel-gray or bluish mineral; black or bluish-black streak; metallic or dull luster. D 4.73–4.86, Mohs hardness 2–2.5. Soluble in hydrochloric acid.
Occurrence:
U.S. (Virginia, Georgia, Arkansas, Lake Superior region, Massachusetts, Vermont, New Mexico), Germany, Australia, India, Canada.
Use:
Manganese ore. For many uses the ore and synthetic material are interchangeable, but pyrolusite is not usable for batteries.

See Manganese Dioxide.