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Cymraeg

Ramsbeckite

Crystal System: Monoclinic
Status of Occurrence: Confirmed Occurrence - 1st UK recording
Distribution: Rare
Chemical Composition: Basic hydrated copper zinc sulphate
Chemical Formula: (Cu,Zn)15(SO4)4(OH)12ยท6H2O
Method(s) of Verification: Penrhiw Mine - XRD (National Museum of Wales, NMW X-795); Brynyrarian Mine - XRD (NHM, London); Dylife Mine - XRD (NHM, London).

Chemical Group:

Geological Context:

Ramsbeckite crystals (1.5 mm), from Penrhiw Mine showing characteristic shape. J.S. Mason Collection (JMPR501). © National Museum of Wales, photo D.I. Green.
Bottle-green ramsbeckite microcrystals associated with pearly, pale blue, schulenbergite from Penrhiw Mine in the Central Wales Orefield. Specimen and photo S.A. Rust. © S.A. Rust.
A deep green, somewhat cylindrical, ramsbeckite crystal with linarite and schulenbergite from Dylife Mine. Specimen and photo S.A. Rust. © S.A. Rust.
Introduction: ramsbeckite occurs in mine tips where sulphide-rich spoil has undergone weathering, and is also known from weathered metalliferous slags. It is invariably associated with other rare Cu-Zn bearing supergene species such as schulenbergite, namuwite and serpierite. The association most frequently occurs within voids in corroded vein carbonates adjacent to part-weathered sulphides. The visual identification of ramsbeckite is assisted by its crystal morphology (diamond-shaped crystals) and colour (a distinctive, lustrous bottle-green).
Occurrence in Wales: only first described as a mineral in 1987, ramsbeckite is one of a considerable number of microcrystalline supergene minerals restricted in their occurrence to the post-mining mineralization environment. The first UK occurrences of ramsbeckite date from the period 1985-1990 (Rust, 1992); however the finds at Penrhiw Mine between 1992 and 1995 set a new standard for the species (Mason & Green, 1995). Since then further minor UK occurrences have been discovered, most of which have been in Central Wales.

Key Localities:

References:

  1. 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.
  2. 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.
  3. 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.
  4. Rust, S.A., 1992. Ramsbeckite, the first three British occurrences. U.K. Journal of Mines and Minerals, No. 11, 24-25.