The Kalahari Manganese Fields are hosted in the rocks of the Transvaal Supergroup, representing the largest known deposit of Manganese in the world. Having produced some of the finest manganese minerals worldwide, including several new species, the deposit was discovered in 1940 by Assmang, and led to the development of a number of well known mines - The N'Chwaning Mines, the Wessels open pit, and the Gloria mine.
The large majority of specimens available online nowdays originate from N'Chwaning II and N'Chwaning III.
Read about the trip down the N'Chwaning II mine the owner of Cape Minerals was invited to attend many years ago here.