Braunite

Braunite is a silicate mineral containing both di- and tri-valent manganese with the chemical formula: Mn²⁺Mn³⁺₆[O₈|SiO₄]. Common impurities include iron, calcium, boron, barium, titanium, aluminium, and magnesium.

Braunite forms grey/black tetragonal crystals and has a Mohs hardness of 6 - 6.5.

It was named after a Mr. Braun of Gotha, Thuringia, Germany.

A calcium iron bearing variant, named braunite II (formula: Ca(Mn³⁺,Fe³⁺)₁₄SiO₂₄), was discovered and described in 1967 from Kalahari, Cape Province, South Africa.

External links

* Mindat
* Webmineral
* Athena mineral

List of minerals