Braunite is a silicate mineral containing both di- and tri-valent manganese with the chemical formula:

Mn<sup>2+</sup>Mn<sup>3+</sup><sub>6</sub>[O<sub>8</sub>|SiO<sub>4</sub>]. 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 Wilhelm von Braun (1790–1872) of Gotha, Thuringia, Germany.

References

  • Webmineral
  • Athena mineral