Vertical variation of selected trace elements in gem deposits from Ratnapura and Buttala gem fields in Sri Lanka

The distribution of selected trace elements in three gem pit profiles, two from the Ratnapura gem field and the other from the Buttala in the South-ea stern Sri Lanka has been studied. The gem minerals are associated with heav y minerals. Since the latter phases are enriched in some transition group e lements, Zr, Th and LREE, these trace elements accumulate in the gem-bearin g layers. Due to intensive weathering and the formation of lateritic horizo ns, Mn, Cr, Cu and V are strongly associated with the Fe-oxide phases. The general chemical composition of the source rocks plays a major role in the Variations of element contents of gem-bearing layers with depth.