Hausmannite

Hausmannite
General
Category	Oxide minerals
Chemical formula	Mn2+Mn3+2O4
Strunz classification	04.BB.10
Identification
Molar mass	228.81
Color	Brownish black, Grayish.
Crystal habit	Massive - Granular - Common texture observed in granite and other igneous rock. Pseudo Octahedral - Crystals show an octahedral outline.
Crystal system	Tetragonal (4/m 2/m 2/m) Space Group: I 41/amd
Cleavage	[001] Perfect
Fracture	Uneven - Flat surfaces (not cleavage) fractured in an uneven pattern.
Mohs scale hardness	5.5
Luster	Submetallic
Streak	dark reddish brown
Specific gravity	4.7 - 4.84, Average = 4.76
Optical properties	Uniaxial (-), e=2.15, w=2.46
Other characteristics	non-radioactive, non-magnetic, Non-fluorescent.

Hausmannite is a complex oxide of manganese containing both di- and tri-valent manganese. The formula can be represented as Mn²⁺Mn³⁺₂O₄. It belongs to the spinel group and forms tetragonal crystals. Hausmannite is a brown to black metallic mineral with Mohs hardness of 5.5 and a specific gravity of 4.8. The type locality is Oehrenstock (Öhrenstock), Ilmenau, Thuringian Forest, Thuringia, Germany. Locations include Batesville, Arkansas, USA; Ilfeld, Germany; Langban, Sweden; and the Ural Mountains, Russia. The best samples have been found in South Africa and Namibia where it is associated with other manganese oxides, pyrolusite and psilomelane and the iron-manganese mineral bixbyite.

External links

• Mineral galleries
• Mindat
• Webmineral

Crystal structure of hausmannite

Hausmannite from Wessels Mine, Kalahari manganese fields, Northern Cape Province, South Africa. Size: 5.8 x 4.3 x 3.5 cm.