Albitites associated with biotite granite. Ririwai, Nigeria.

Major Minerals:

Columbite, haematite, zircon

Minor Minerals:

Ilmenite, magnetite, uranothorite, cassiterite, monazite, xenotime

Trace Minerals:

Include TiO2 minerals, bästnasite, fluocerite group minerals, sphalerite, galena, pyrite, molybdenite


The opaque and accessory minerals are euhedral to subhedral and coarse-grained. Zircon is zoned with inner inclusion-rich zones containing thorite and haematite and an outer inclusion-free zone. Compositional zoning, especially in the outer zone, is marked and seen by reflectance variations. Ilmenite and columbite are optically and compositionally zoned. Coarse-grained haematite overgrows zircon, and complex intergrowths between ilmenite-haematite and columbite-haematite are common. Primary sulphides are very minor in amounts.


Ixer et al., 1987; Pointer et al., 1988a,b