Mineral Database (Saesneg yn unig)

Mineral Database (Saesneg yn unig)
Mineralogy of Wales

Pyrobelonite

Crystal System: Orthorhombic
Formula: PbMn(VO4)(OH)
Status of Occurrence: Confirmed Occurrence - 1st UK recording
Distribution: Rare
Chemical Composition: Lead manganese vanadate hydroxide
Method(s) of Verification: Ty-coch - EMPA & reflected light microscopy (Criddle & Symes, 1977).
Chemical Group:
  • Vanadates
Geological Context:
  • Hydrothermal : limestone hosted hematite deposits
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 Ty-Coch. This represents only the second world-wide occurrence and first British occurrence of pyrobelonite.

Key Localities:
  • Ty-coch, near Porthcawl, South Wales: pyrobelonite occurs as a minor constituent in manganese ore. Criddle & Symes (1977) identified pyrobelonite in one ore type from Ty-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.
References:
  • Criddle, A.J., & Symes, R.F., 1977 Mineralization at Ty-coch, Glamorgan (Mid Glamorgan), Wales: the second occurrence of pyrobelonite. 

    Mineralogical Magazine, 41, 85-90.