Magnetite

Name:
Magnetite
Detailed information:

M Formula:	Fe3O4 often with titanium or magnesium
Properties:
Black mineral, black streak, submetallic or dull to metallic luster. Contains 72.4% iron. Readily recognized by strong attraction by magnet. Soluble in powder form in hydrochloric acid. Decomposes at 1538C to ferric oxide Fe2O3, d 4.9–5.2, hardness 5.5–6.5.

See Iron Oxide, Black.