Hausmannite

specimen number:
2282116

location:
N'Chwaning II Mine, Northern Cape, South Africa

description:
A fine thumbnail for the species, the specimen consists of a sharp cluster of lustrous black hausmannite crystals. This is in very good condition.

The N'Chwaning II mine, located near Black Rock in the Kalahari Manganese Field of the Northern Cape Province, South Africa, is an underground mining operation renowned for its diverse assemblage of crystallized manganese minerals. Geologically, the deposit is situated within the Hotazel Formation of the Paleoproterozoic Transvaal Supergroup, which represents a massive sedimentary manganese formation consisting of alternating layers of manganese ore and banded ironstones. The mineralization occurred through volcanic-sedimentary deposition followed by hydrothermal alteration, creating a low-grade hydrothermal zone rich in rhodochrosite, ettringite, inesite, and various calcium-manganese silicates. Underground mining operations at the N'Chwaning II shaft commenced in 1981 under the Associated Manganese Mines of South Africa Limited (Assmang), utilizing mechanized room-and-pillar mining methods to extract high-grade metallurgical and chemical manganese ore. The facility has maintained continuous commercial extraction and processing of these manganese reserves, with operations extending into the twenty-first century.

Hausmannite is a complex manganese oxide mineral that belongs to the spinel group. It typically occurs as a primary or secondary mineral in hydrothermal veins, contact metamorphic deposits, and layered manganese sedimentary formations. The mineral forms opaque, dark brown to black crystals that often exhibit distinct tetragonal pyramidal habits, and it serves as an important industrial ore of manganese when found in massive aggregates.

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