Mineral Database (Saesneg yn unig)
Scheelite
Crystal System: Tetragonal
Formula: CaWO4
Status of Occurrence: Confirmed Occurrence
Distribution: Rare
Chemical Composition: Calcium tungstate
Method(s) of Verification: Shadow Gully - reflected light microscopy
Chemical Group:
- Sulphites, Chromates, Molybdates & Tungstates
Geological Context:
- Hydrothermal
- Metamorphic
Introduction: scheelite occurs in high temperature tungsten-bearing mineral veins, and also in contact metamorphic mineral deposits.
Occurrence in Wales: scheelite is an extremely rare mineral in Wales, typically occurring as microscopic grains and inclusions only detectable by microprobe analysis.
Key Localities:
- Harlech Dome area, Gwynedd: rare scheelite is present with pyritic mudstones of the Haffoty Formation of Cambrian age, exposed in the Harlech Dome area (Bennett, 1987).
- Shadow Gully, Snowdon, Gwynedd: scheelite is developed between magnetite grains within a magnetite dominated breccia-vein complex trending NW, exposed within the gully (Bevins & Mason, 1998).
References:
- The Cambrian manganese deposits of North Wales. Unpublished Ph.D. thesis, University of Leeds.
- Welsh Metallophyte and metallogenic evaluation project: Results of a Minesite Survey of Gwynedd. National Museums of Wales, Cardiff.
