Pyrobelonite

Crystal System: Orthorhombic
Status of Occurrence: Confirmed Occurrence - 1st UK recording
Distribution: Rare
Chemical Composition: Lead manganese vanadate hydroxide
Chemical Formula: PbMn(VO4)(OH)
Method(s) of Verification: Tŷ Coch - EMPA & reflected light microscopy (Criddle & Symes, 1977).

Chemical Group:

  • Vanadates

Geological Context:

  • Hydrothermal: limestone hosted hematite deposits
Thin film of pyrobelonite in ore at T? Coch. Specimen National Museum of Wales (NMW 87.73G.M.29), photo D.I. Green, © National Museum of Wales.
Introduction: pyrobelonite is an extremely rare member of the adelite group, found in iron-manganese mineral deposits.
Occurrence in Wales: Criddle and Symes (1977) identified pyrobelonite during the course of a reflected light study of manganese and iron ores collected from some small spoil tips at Tŷ Coch. This represents only the second world-wide occurrence and first British occurrence of pyrobelonite.

Key Localities:

  • Tŷ Coch, near Porthcawl, South Wales: pyrobelonite occurs as a minor constituent in manganese ore. Criddle & Symes (1977) identified pyrobelonite in one ore type from Tŷ Coch, forming solitary grains and clusters of individual grains and compound grains in calcite, with braunite aggregates, hausmannite crystals and partial pseudomorphs thereof, and as lamellae between barite laths. Typically the grain size ranges from 20 μm up to 1 cm and is often intimately associated with vanadinite (Criddle & Symes, 1977). In addition it forms veinlets generally less than 0.5 mm thick, which can be traced for up to 3 cm. It has an adamantine to submetallic lustre, is black to deep red in colour and produces a bright orange powder.

There are no key localities for this specimen.

References:

  1. Criddle, A.J., & Symes, R.F., 1977. Mineralization at Tŷ Coch, Glamorgan (Mid Glamorgan), Wales: the second occurrence of pyrobelonite. Mineralogical Magazine, 41, 85-90.

There are no references for this specimen.