Cause of violet coloration on pyromorphite(Pb₅(PO₄)₃Cl) from Ogoya mine, Japan

Abstract

We attempted to find a cause of violet coloration on pyromorphite from Ogoya mine, Japan. Polished section along the c-axis showed violet bands normal to the c-axis. Qualitative EPMA analysis showed presence of Ca and Zr as impurities and further quantitative analysis showed higher (1.5 times) concentration of Zr in violet band. While further investigation is needed, our results strongly suggest Zr as the cause of coloration of the present specimen.