Crystal System: Hexagonal
Status of Occurrence: Confirmed Occurrence
Distribution: Uncommon
Chemical Composition: Calcium phosphate hydroxide
Chemical Formula: Ca5(PO4)3(OH)
Method(s) of Verification: Brynamman - XRD (Baqri & Hodson, 1979).

Chemical Group:

  • Phosphates

Geological Context:

  • Sedimentary: diagenetic
Introduction: hydroxylapatite belongs to the apatite group of minerals but is much less common than fluorapatite. It may form by the interaction of limestone with guano deposits.
Occurrence in Wales: only one occurrence of hydroxylapatite is known from Wales. Baqri & Hodson (1979) reported that coal partings or ‘dirt bands’ in the Lower Hornlo (Red Vein) seam in the neighbourhood of Brynamman, West Glamorgan contained up to 40% hydroxylapatite. This appears to be the first record of hydroxylapatite in the British Isles. The identification requires clarification.

Key Localities:

There are no key localities for this specimen.


  1. Baqri, R. & Hodson, F., 1979. Apatite in South Wales anthracite. Geological Magazine, 30, 645-647.