VERNADITE IN GORIAJHOR MANGANESE ORES, GANGPUR GROUP, INDIA

Characteristics of vernadite in manganese ores from Gangpur Group of r ocks, Goriajhor Formation, Sundargarh district, Orissa, have been desc ribed. This terrestrial vernadite is distinguished from delta-MnO2 in marine manganese nodules by its well ordered crystallinity and thinner fibrils of submicron size. It appears to be chemically homogenous wit h the proposed formula: (Ba, K, Fe) MnO2.nH(2)O. This vernadite probab ly originated through solution, precipitation and redeposition under s upergene conditions and later transformed into cryptomelane or romanec hite.