Wan Fuad Wan Hassan

Geochemistry and mineralogy of TaNb rutile from Peninsular Malaysia

Chemical and mineralogical studies undertaken on TaNb rutile from Peninsular Malaysia are discussed. NbTa rutile is found as grains in alluvial tin concentrates, mostly from the Western Tin Belt. Pure rutile shows tetragonal prismatic form but TaNb rutile, due to high degree of substitution of Ti by Nb and Ta, is distorted in its growth, resulting in “wedge” e(101) or “spear” s(111) terminations. Due to high Nb, Ta and Fe contents, NbTa rutile crystal is highly inhomogenous and magnetic. Polished sections reveal the presence of exsolution phases of columbite-ixiolite, cassiterite, pure rutile and inclusions of ilmenite. Bulk composition shows the presence of niobium (9–17% Nb2O5), tantalum (5–26% Ta2O5), iron (5–13% FeO), tin (2–7% SnO2), tungsten (0.5–1.0% WO3), manganese (0.2–1.0% MnO) and zirconium (0.0–0.2% ZrO2) in the dominantly Ti-bearing host.