Silver

Silver


Composition: Ag
Crystal System : Cubic
Colours: White, silver-white, yellowish-silver
Lustre : Metallic
Hardness (H) : 2.5-3.0
Specific Gravity (S.G) : 10.5

Distribution

Rare. (Relatively common, however, in the third oxidation zone.)

Occurrence

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

Notable Finds

The best specimens of silver are from 43 and 44 levels in the third oxidation zone, with small, euhedral octahedral crystals to 5 mm. Gebhard (1999) describes a visit to 43 Level, and observing leaves of silver amalgam protruding from a face of massive cuprite ore.

Paragenetic and General Notes

In the first oxidation zone, silver is sparsely distributed as thin platelets and veinlets in chalcocite rich ore.

Silver from Tsumeb's third oxidation zone has a slightly yellowish (golden) hue, and typically contains c. 25% mercury. It is therefore silver amalgam (Gebhard and Schlüter, 1994). The occurrence of octahedral crystals, albeit small ones (to 5 mm) is exceptional for native silver.

A black porous variety of silver amalgam also occurs in the third oxidation zone.