Crystal System: Monoclinic
Status of Occurrence: Confirmed Occurrence - 2nd UK recording
Distribution: Rare
Chemical Composition: Lead copper arsenate sulphate hydroxide
Chemical Formula: Pb2Cu(AsO4)(SO4)(OH)
Method(s) of Verification: Dolyhir Quarry - XRD and EDS at Manchester Museum (X-ray reference MANCH:XRD1297).

Chemical Group:

  • Arsenates
  • Sulphates

Geological Context:

  • Supergene: in situ natural oxidation & weathering deposits
Pale green arsentsumebite microcrystals to 0.05 mm in length from Dolyhir Quarry. Photo D.I. Green, © D.I. Green.
Scanning electron micrograph of a small fragment (from National Museum of Wales specimen NMW 2007.1G.M.1) bearing blocky arsentsumebite crystals from Dolyhir Quarry. Image D.I. Green, © D.I. Green.
Introduction: a rare secondary mineral formed in the oxidation zone of hydrothermal polymetallic ore deposits.
Occurrence in Wales: discovered recently forming drusy crusts of blocky pale mint green crystals up to 0.1 mm on edge on oxidized lead- and copper-rich veinstone collected from Dolyhir Quarry in the mid-1990s (Hubbard et al., 2007).

Key Localities:

  • Dolyhir Quarry, Old Radnor, Powys: a recent addition to the list of unusual species that occur at this quarry. Arsentsumebite has only been found on a few small fragments of oxidized galena-tennantite-bearing veinstone collected during the mid-1990s.

There are no key localities for this specimen.


  1. Cotterell, T.F., Green, D.I., Hubbard, N., Mason, J.S., Starkey, R.E. and Tindle, A.G., 2011. The Mineralogy of Dolyhir Quarry, Old Radnor, Powys, Wales. UK Journal of Mines and Minerals, 32, 5-61.
  2. Hubbard, N., Green, D.I. and Cotterell, T.F., 2007. Arsentsumebite from Dolyhir Quarry, Old Radnor, Powys. UK Journal of Mines and Minerals, 28, 9-10.

There are no references for this specimen.