No CrossRef data available.
Published online by Cambridge University Press: 14 March 2018
An occurrence of stilpnomelane in calcite veins cutting an Ordovician sedimentary iron-ore body has yielded good material for optical and chemical study; data for both ferro- and ferri-stilpnomelane are presented. Associated pyrrhotine, ilmenite, and apatite are briefly described, and a chemical analysis of the apatite shows it to be an extremely pure fluorapatite.