Composition: PbAl3(As0.5,S0.5,O4)2(OH)6
Crystal System : Trigonal
Colours: White, pale-grey, green
Lustre : Chalky, dull
Hardness (H) : 4.5
Specific Gravity (S.G) : 4.24


Very rare. First and second oxidation zone, but very scarce in the latter.


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

Paragenetic and General Notes

Hidalgoite was among the earliest secondary minerals identified at Tsumeb (Maucher, 1908), clearly demonstrating its occurrence in the upper portion of the first oxidation zone.  It occurs as rare yellow-green masses (Pinch and Wilson, 1977), or as very rare crystals on quartz (Gebhard, 1999).