Crystal System: Monoclinic
Status of Occurrence: Unconfirmed Occurrence
Chemical Composition: Uranium calcium yttrium cerium titanium iron oxide
Chemical Formula: (U,Ca,Y,Ce)(Ti,Fe)2O6
Method(s) of Verification: Llanddulas - EMPA (no analyses published, Eakin & Gize, 1992).
Introduction: brannerite is a uranium-bearing mineral which forms a series with thorutite, (Th,U,Ca)Ti2(O,OH)6 and is dimorphous with orthobrannerite (has the same chemical composition but a different crystal lattice). Brannerite has been recorded from gold placer deposits and in pegmatites where it forms as an alteration product after uraninite. Brannerite crystals are commonly metamict (where the crystal structure is destroyed by radioactive damage).
Occurrence in Wales: Eakin & Gize (1992) suggested that alteration rims on highly altered, wedges-shaped mineral inclusions (probably of uraninite) in bitumen from Llanddulas, Clwyd may be brannerite. No further data is available at present.
There are no key localities for this specimen.
- Eakin, P.A. & Gize, A.P., 1992. Reflected-light microscopy of uraniferous bitumens. Mineralogical Magazine, 56, 85-99.