Magnesioferrite

Magnesioferrite is a magnesium iron oxide mineral, a member of the magnetite (q.v.) series of spinels. Magnesioferrite crystallizes as black metallic octahedral crystals. It is named after its chemical composition of magnesium and ferric iron. The density is 4.6 - 4.7 (average = 4.65), and the diaphaniety is opaque. Crystalline - Fine - Occurs as well-formed fine sized crystals. Massive - Granular - Common texture observed in granite and other igneous rock. Its hardness is 6-6.5 - Orthoclase-Pyrite and the luminescence is non-fluorescent. Its luster is metallic and its streak is dark red. Sources include from Vesuvius and Stromboli, Italy.