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www.mineralgallery.co.za Minerals A-E |
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Braunite II |
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Name
Braunite II
Chemistry
Ca(Mn,Fe)14SiO24
Uses
As a collectors specimen and as a minor ore of manganese
Color
Black
Hardness
6-6.5
Specific gravity
4.7-4.8
Streak
White
Crystals
It forms multiple pyramidal crystals.
Accompanied by:
Hausmannite, brucite, manganite,
Similar to:
Hausmannite
Braunite was first discovered in the Kalahari Manganese field in 1945 and described as ferrian braunite.
It is not regarded as a distinct species but rather as a compositional variety of braunite. It was renamed braunite II by De Villiers and Herbstein in 1967 and it's crystal structure was determined by De Villiers in 1980.
Metallic grey braunite II crystals have come from Wessels, Black Rock and N'Chwaning II. The crystals are typical dipyramidal with complex terminations. In 1995 crystals up to 3 cm were found at the Wessels mine. This is the only locality where this rare crystal has been found.
