dichromium iron tetraoxide

Chemical properties

Iron-black to brownish-black color, dark-brown streak, metallic to submetallic luster. Mohs hardness 5.5.

Physical properties

Habit: massive, granular, nuggets.
Color: black or brownish black.
Luster: metallic.
Diaphaneity: opaque.
Streak: brown.
Cleavage: none.
Twinning: {111}.
Fracture: uneven to conchoidal.
Others: weakly magnetic.
Thermal conductivity of 1.73–2 W.m^–1K^–1

The Uses of dichromium iron tetraoxide

Only commercial source of chromium and its compounds.

Definition

A natural oxide of ferrous iron and chromium, sometimes with magnesium and aluminum present. Usually occurs in magnesium and iron-rich igneous rocks.

Hazard

A confirmed carcinogen.

Industrial uses

Only commercial source of chromium used in the metallurgical industry (85%) mainly as Fe–Cr for steelmaking, in the refractory and foundry market (8%) and in the chemical industry (7%).

Safety Profile

Confirmed human carcinogen during ore processing. Human mutation data reported. See also CHROMIUM COMPOUNDS and IRON.