Massicot


Composition: PbO
Crystal System : Orthorhombic
Colours: Yellow, reddish-yellow
Lustre : Oily, earthy, dull
Hardness (H) : 2
Specific Gravity (S.G) : 9.64
References: Gebhard (1999)

Distribution

Very rare. First oxidation zone (?). Third oxidation zone (43 Level).

Occurrence

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

Notable Finds

In the third oxidation zone as sparse yellow coatings on hydrocerussite in the so-called "Lead Pocket", on 43 Level (Gebhard, 1999).

Paragenetic and General Notes

Biehl (1919) and Pufahl (1920) each described earthy lemon-yellow and ochre-yellow masses of massicot from the upper levels. Gebhard (1999) notes that massicot was observed as yellow-brown coatings on and between anglesite crystals in the upper levels of the first oxidation zone.   However, Strunz et al. (1958), and Lombaard et al. (1986), both question the validity of massicot at Tsumeb. 

The more recent discovery in the third oxidation zone (43 Level, the "Lead Pocket"), where massicot occurs as sparse coatings on hydrocerussite-encrusted cerussite crystals, is not questioned.