Strontianite

Crystal System: Orthorhombic
Status of Occurrence: Confirmed Occurrence
Distribution: Rare
Chemical Composition: Strontium carbonate
Chemical Formula: SrCO3
Method(s) of Verification: Benallt Mine - XRD (NHM, x2980); Nant Mine - XRD(NHM, x7903); Penarth - XRD (National Museum of Wales, NMW X-1016)

Geological Context:

  • Hydrothermal: Mississippi Valley Type veins
Scanning electron micrograph of spiky strontianite crystals from Penarth, South Wales. National Museum of Wales Collection. Image T.F. Cotterell, © National Museum of Wales.
Strontianite filling internal cavities of a coiled nautiloid shell which is lined with calcite. Lavernock Point. National Museum of Wales Collection (NMW 2001.11G.M.1). Photo D.I. Green, © National Museum of Wales.
Introduction: strontianite occurs as a minor component of low-temperature hydrothermal mineral veins, particularly those carrying barium minerals. Baryte and strontianite frequently occur together.
Occurrence in Wales: the presence of strontianite in Wales has come to light only in recent years. Four localities were known by the early 1990s (Bevins, 1994) and a fifth has since been added. Interestingly, the occurrences, restricted to three small areas, are diverse in terms of their geological setting: unfortunately, however, detailed information is lacking on all occurrences outside of South Wales.

Key Localities:

  • Benallt and Nant mines, Llŷn, Gwynedd: the presence of strontianite, from these manganese deposits, is recorded only by Natural History Museum X-ray diffraction data, no further details are available.
  • Penarth and Lavernock, South Wales: reported from Penarth as a small radiating mass of white acicular crystals (NMW 85.41G.M1), collected by A. Dean (Bevins, 1994); subsequently material from a mineralized fault cutting Rhaetic strata was discovered between Penarth and Lavernock Point, in which radiating spheres of acicular strontianite to 3 mm were present. Associated minerals were calcite and celestine. This find was made after a cliff-fall by members of the South Wales branch of the Russell Society and reported in the Mineral News section of the UK Jornal of Mines & Minerals (no. 16) in 1996.
  • Pennant Mine, St Asaph, Clwyd: strontianite is recorded from a single specimen in the Natural History Museum collection (B.M. 1985, M1 11289). No further details are available.

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.

There are no references for this specimen.