Crystal System: Cubic
Status of Occurrence: Unconfirmed Occurrence
Distribution: Rare
Chemical Composition: Antimony oxide
Chemical Formula: Sb2O3
Method(s) of Verification: not known

Chemical Group:

  • Oxides & Hydroxides

Geological Context:

  • Supergene: in situ natural oxidation & weathering deposits
Introduction: sénarmontite is a secondary mineral formed by the oxidation of antimony-bearing minerals in hydrothermal mineral deposits.
Occurrence in Wales: Readwin (1888) recorded sénarmontite from the Dolgellau Gold-Belt however, no further details are known. Given the rarity of antimony-bearing minerals in the Dolgellau region this occurrence must be viewed with uncertainty.

Key Localities:

  • Dolgellau Gold-belt, Gwynedd: recorded without description by Readwin (1888).


  1. Readwin, T.A., 1888. Gold in Wales. London, 12pp.