Variation in etch behaviour of jacobsite with different cell dimensions

Abstract

During the study of polished sections of manganese ores from the Kodur Group of mines, Srikakulam Dt., Andhra Pradesh, India, I came across three different types of jacobsite, associated with other manganese minerals like braunite, hausmannite, pyrolusite, cryptomelane, coronadite and γ-MnO². It is the interesting variation in the colour and etch behaviour in the different types of jacobsite that attracted my attention, and investigations to find out the cause of such variation were attempted.