Anglesite

Anglesite


Composition: PbSO4
Crystal System : Orthorhombic
Colours: Colourless, white, yellow, very pale blue, grey, black
Lustre : Adamantine, vitreous, resinous
Hardness (H) : 2.5-3.0
Specific Gravity (S.G) : 6.37-6.39
References: Keller (1977a)

Distribution

Common. Occurs in all three oxidation zones.

Occurrence

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

Notable Finds

Very large crystals to 500 mm on a face have been reported (Key, 1996).

Paragenetic and General Notes

Anglesite is a common secondary mineral, important in lower pH parageneses and almost always closely associated with galena. It occurs most commonly as sharp, angular, diamond-shaped crystals, as thick tabular (blocky) crystals, or as thin tabular crystals, but many forms and habits have been encountered (Key, 1996).

Anglesite is a key mineral of Keller's (1977) "Type II" paragenesis (i.e. minerals forming at a lower pH range). Commonly as the only secondary mineral on, or in cavities in, galena-rich massive sulphide ores. Keller (op.cit.) identified two distinct parageneses with anglesite:

(1) Primary sulphide >> beudantite >> carminite >> anglesite >> gartrellite.

(2) Primary sulphide >> scorodite >> arsentsumebite >> anglesite >> brochantite >> cerussite (ps. after anglesite).

Anglesite has been reported to form pseudomorphs after schultenite (rare; Spencer and Mountain, 1926).

The following minerals have been reported to form pseudomorphs after anglesite: arsentsumebite (rare); cerussite (common).