Crystal System: Monoclinic
Status of Occurrence: Confirmed Occurrence - 1st UK recording
Chemical Composition: Lead antimony sulphide
Chemical Formula: Pb4Sb6S13
Method(s) of Verification: Bwlch Mine - EMPA (Bevins et al., 1988)
- Hydrothermal: epithermal polymetallic veins & pipes
Introduction: robinsonite is occasionally found with stibnite, galena and various lead-antimony sulphosalts in complex hydrothermal vein and breccia assemblages typical of the epithermal Pb-Sb association. As with many of the Pb-Sb sulphosalts, robinsonite is almost always impossible to identify in hand specimen and even in polished section these minerals can be remarkably difficult to distinguish. Consequently, verification requires detailed analytical techniques in the majority of occurrences.
Occurrence in Wales: the only record of robinsonite from Wales is that which resulted from detailed investigations of the antimony mineralization at Bwlch Mine near Deganwy on the North Wales coast (Bevins et al., 1988).
- Bwlch Mine, Deganwy, Gwynedd: intergrown with other Pb-Sb sulphosalts (especially semseyite, plagionite and zinkenite) and with stibnite in small (<2 cm) patches and stringers associated with quartz in a stockwork-like group of veins hosted by altered spherulitic acid ash-flow tuff (Bevins et al., 1988).
- Bevins, R.E., Alderton, D.H.M. & Horak, J.M., 1988. Lead-antimony mineralisation at Bwlch Mine, Deganwy, Wales. Mineralogical Magazine, 52, 391-394.