Marokite

marokite

jouravskite

hausmannite

braunite

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Formula: CaMn3+2O4
Multiple oxide, marokite supergroup, manganese-bearing mineral
Crystal System: Orthorhombic
Specific gravity: 4.64 measured, 4.63 calculated
Hardness: 6½
Streak: Reddish brown
Colour: Black
Environments

Hydrothermal environments

Marokite occurs in hydrothermal manganese oxide deposits (HOM).

Localities

At the type locality, the Tachgagalt mine, Tansifite Caïdat, Agdz Cercle, Zagora Province, Drâa-Tafilalet Region, Morocco, marokite occurs in a gangue of manganese-free calcite and baryte, associated with hausmannite, braunite, rare crednerite and polianite and as yet unidentified minerals. In the type specimen marokite occurs in large (up to 5 x 1.5 x 05 cm3) untwinned orthorhombic crystals. Macroscopically, marokite is black, opaque with dark red internal reflections, bright lustre and a reddishbrown streak (AM 49.817 ).
Other associated minerals include jouravskite, cryptomelane and dolomite (HOM).

At the Black Rock Mine, Black Rock, Kalahari manganese field, Northern Cape, South Africa, marokite was found in one sample only, which has a fibrous appearance owing to densely packed slender crystals. Marokite occurs as remnants in an unidentified alteration product which is associated with pyrolusite in the form of possible vug fillings and veins, cryptomelane as veins and opaline silica in vugs (AM 53.495).

At the N'Chwaning II mine, N'Chwaning Mines, Kuruman, Kalahari manganese field, Northern Cape, South Africa, marokite is associated with pyrolusite, cryptomelane and opal (HOM).

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