Pyrite

Pyrite


Composition: FeS2
Crystal System : Cubic
Colours: Bright brass-yellow
Lustre : Metallic
Hardness (H) : 6.0-6.5
Specific Gravity (S.G) : 4.9-5.2

  

Distribution

Very common. Occurs throughout the Tsumeb deposit.

Occurrence

  • Hypogene
  • 1st Oxidation Zone
  • 2nd Oxidation Zone
  • 3rd Oxidation Zone

Notable Finds

Veins of massive pyrite were encountered below 38 Level.

Paragenetic and General Notes

By the standards of most polymetallic base metal deposits Tsumeb is iron-defficient and, therefore, pyrite is a very common, though generally not abundant, component of the hypogene (sulphide) ores.

Specimen quality material is relatively uncommon. Crystals are typically only a few mm in size, although a few examples with crystals to c.30 mm have been found. Cube, pyritohedron and octahedron faces are all observed (Pinch and Wilson, 1977).

According to Gebhard, pyrite was relatively common in the upper levels and again in the deepest levels, where pyrite veins of up to 1 m in thickness were observed cutting tennantite ores. Lombaard et al. (1986) show that pyrite was a significant constituent of the ore from c. 5 Level, down to c. 22 Level, locally accounting for c.10% of the ore by volume. It was again important from c. 33 Level downwards, and from 38 Level down, pyrite accounted for c. 20% of the ore by volume.