Manganese ores – manganite and pyrolusite
Manganite, MnO(OH) and pyrolusite, MnO2, are two of the most important raw materials for manganese. In the area from Ålefjærfjorden to Vennesla, five manganese deposits have been described: Lømsland, Dalen mine, Kostølheia, Kvivigdalen mine and Kjevik mine. The most famous one is probably the Kvivigdalen mine at Kostøl. Here, in the 1890s, pyrolusite was once detected, and mining began in 1896. In the following years, there was intermittent operation until 1919, when it was no longer possible to continue. A total of 65 tonnes of ore with a concentration of approx. 40% manganese is said to have been extracted from the Kvivigdalen mine.
Manganese is a silver-white, hard, and brittle metal that may resemble iron. Its clearly most important use is as an alloying metal in steel, including stainless steel. It is also used in aluminum alloys. Manganese dioxide is used in alkaline batteries.
The sample on display is manganite from the Bjerkvik manganese deposit near Kjevik, Kristiansand.