Mineral Database

Mineral Database
Mineralogy of Wales

Hübnerite

Crystal System: Monoclinic
Formula: Mn2+WO4
Status of Occurrence: Confirmed Occurrence
Distribution: Rare
Chemical Composition: Manganese tungstate
Method(s) of Verification: Diphwys Mine by XRD (XRD no. NMW X-2178) and EDS at the National Museum of Wales; Hendre Mine by XRD (no. NMW X-2195) at the National Museum of Wales. The analytical data is presented in Cotterell et al. (2010).

12 mm long dark brown, bladed, hübnerite crystal from Hendre Mine, Llanaber, Merionethshire. National Museum of Wales specimen no. NMW 2008.43G.M.9

Chemical Group:
  • Sulphites, Chromates, Molybdates & Tungstates
Geological Context:
  • Hydrothermal : alpine type veins
Introduction: hübnerite is the manganese-dominant member of the wolframite group. It is generally considered to be a high-temperature mineral, found in hydrothermal veins, greisens, granitic pegmatites and as a detrital mineral in some alluvial deposits.
Occurrence in Wales: there are no significant high-temperature mineral deposits in Wales. Consequently, tungsten-bearing minerals are rare. An unusual, apparently low temperature, occurrence within alpine-type fissure veins within the Cambrian manganese ore bed is described by Cotterell et al. (2010).
Key Localities:
  • Diphwys Mine, Bontddu, Dolgellau, Gwynedd: dark brown bladed hübnerite crystals were discovered in thin (less than 3 mm wide) quartz-dominated alpine-type fissure veinlets within blocks of bedded manganese ore found near to a loading bay at the base of the incline (Cotterell et al., 2010).
  • Hendre Mine, Moelfre, Llanbedr, Gwynedd: coarse (up to 12 mm in length) dark brown bladed crystals of hübnerite occur within quartz-carbonate veins cutting pale, carbonate dominated bedded manganese ore (Cotterell et al., 2010). A number of specimens are in the collections at the National Museum of Wales (see for example NMW 2008.43G.M.9).
References:
  • Cotterell, T.F., Mason, J.S. and Dean, A.C., 2010 Hübnerite in alpine-type fissure veinlets in the Cambrian manganese ore bed, Harlech, Wales.  Journal of the Russell Society, 13, 47-52.