Formula: Mn3+O(OH)

Colour: gray-black, black

Lustre: Resinous, Sub-Metallic, Dull

Hardness: 4

Specific Gravity: 4.29 – 4.34

Crystal System: Monoclinic

Name: Named in 1827 by Wilhelm Karl von Haidinger in allusion to the manganese content.

Type Locality: Manganese deposit, Ilfeld, Harztor, Nordhausen District, Thuringia – Germany

Polymorph of: Feitknechtite, Groutite

Frequently as well-formed crystals or tight aggregates with a fibrous structure due to the mineral’s perfect cleavage. May be compact fine-grained or in botryoidal formation.