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Cymraeg

Serpierite

Crystal System: Monoclinic
Status of Occurrence: Confirmed Occurrence
Distribution: Uncommon
Chemical Composition: Calcium copper zinc sulphate hydroxide hydrate
Chemical Formula: Ca(Cu,Zn)4(SO4)2(OH)6.3H2O
Method(s) of Verification: XRD from these mines: Brynarian - (NMW X-1038); Dylife - (NMW X-39 & NHM 4130F); Eaglebrook - (NMW X-772, 1037 & 1125); Frongoch – (NHM); Henfwlch - (NMW X-1344); Nant-y-creiau - (NMW X-1270); Penrhiw - (NMW X-883); Ystrad Einion – (NMW X-1044)

Chemical Group:

Geological Context:

Serpierite rosettes to 5 mm from Ystrad Einion Mine, in the Central Wales Orefield. S.A. Rust Collection (no. 1973). Photo M.P. Cooper, © National Museum of Wales.
Radiating aggregates of serpierite crystals (up to 1 mm long) from Ystrad Einion Mine, Central Wales. J.S.Mason Collection (no. JMYE006). Photo M.P. Cooper, ©, National Museum of Wales.
Feathery sprays of pale blue serpierite from Eaglebrook Mine in the Central Wales Orefield. Specimen and photo S.A. Rust. © S.A. Rust.
Introduction: serpierite is an attractive secondary species which, forms in post-mining supergene environments associated with primary zinc-copper mineralization.
Occurrence in Wales: Jones & Moreton (1977) produced the first written account of serpierite from Wales, describing sky-blue tufted aggregates from Dylife Mine in the Central Wales Orefield. Specimens had, in fact, been collected from Dylife from the late 1960’s (National Museum of Wales Mineral Collection numbers NMW 68.378.GR.27 & NMW 68.576.GR.17) by D. Hardman and R.S.W. Braithwaite. Many more occurrences have come to light from the Central Wales Orefield including, stunning freestanding crystal sprays from underground localities such as Ystrad Einion Mine (Mason & Rust, 1997) and Henfwlch Mine (T.F. Cotterell, unpublished data). The best Ystrad Einion specimens are considered to be some of the finest ‘natural’ serpierite collected in the British Isles (Mason & Rust, 1997). Most occurrences, however, are derived from mine dumps. The discovery of flat-lying radiating sprays of crystals from Llanegan Mine on the Llŷn in Gwynedd by Dr. D. Roe represents, the only occurrence of serpierite outside of the Central Wales Orefield.

Key Localities:

There are no key localities for this specimen.

References:

  1. Bevins, R.E., 1994. A Mineralogy of Wales National Museum of Wales, Geological Series No. 16, Cardiff, 146pp.
  2. Braithwaite, R.S.W., 1982a. Wroewolfeite in Britain. Mineralogical Record, 13, 167-174.
  3. Camm, G.S., 1993. The Minerals and Mines of the Principality of Wales. The Natural History Museum, London. 231pp.
  4. Green, D.I., Rust, S.A. & Mason, J.S., 1996. Classic British mineral localities: Frongoch Mine, Dyfed. UK Journal of Mines & Minerals, 17, 29-38.
  5. Jones, A.D., 1983. Nant-y-Cagl. Mineral Realm, 3, 42-76.
  6. Jones, J.A. & Moreton, N.J.M., 1977. The Mines and Minerals of Mid-Wales 40pp.
  7. Mason, J.S. & Green, D.I., 1995. Supergene minerals including exceptional ramsbeckite from Penrhiw Mine, Ystumtuen, Dyfed. UK Journal of Mines & Minerals, 15, 21-27.
  8. Mason, J.S. & Rust, S.A., 1997. The Mineralogy of Ystrad Einion Mine, Dyfed, Wales. U.K. Journal of Mines and Minerals, 18, 33-36.
  9. Rust, S., 1985. British Micro Localities. No. 12: Esgair Hir Mine (SN 734913), Ceulanymaesmawr, Dyfed, Wales British Micromount Society Newsletter. 13. 13-14.
  10. Rust, S.A. & Mason, J.S., 1994. An unusual occurrence of arsenate minerals at Gwaith-yr-Afon mine, Dyfed, Wales. Journal of the Russell Society, 5(2), 109-113.
  11. Rust, S.A. & Mason, J.S., 1988. The minerals of Esgair-Hir mine, Dyfed, Wales. UK Journal of Mines & Minerals, 5, 35-43.

There are no references for this specimen.