Braunite is a silicate

Silicate

A silicate is a compound containing a silicon bearing anion. The great majority of silicates are oxides, but hexafluorosilicate and other anions are also included. This article focuses mainly on the Si-O anions. Silicates comprise the majority of the earth's crust, as well as the other...

 mineral containing both di- and tri-valent

Valence (chemistry)

In chemistry, valence, also known as valency or valence number, is a measure of the number of bonds formed by an atom of a given element. "Valence" can be defined as the number of valence bonds...

 manganese

Manganese

Manganese is a chemical element, designated by the symbol Mn. It has the atomic number 25. It is found as a free element in nature , and in many minerals...

 with the chemical formula

Chemical formula

A chemical formula or molecular formula is a way of expressing information about the atoms that constitute a particular chemical compound....

:
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 the alderman Braun of Gotha

Gotha (district)

Gotha is a Kreis in the middle of Thuringia, Germany. Neighboring districts are Unstrut-Hainich, Sömmerda, the district-free city Erfurt, Ilm-Kreis, Schmalkalden-Meiningen and the Wartburgkreis.-History:...

, Thuringia

Thuringia

The Free State of Thuringia is a state of Germany, located in the central part of the country.It has an area of and 2.29 million inhabitants, making it the sixth smallest by area and the fifth smallest by population of Germany's sixteen states....

, Germany

Germany

Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...

.

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

South Africa

The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...

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