Abstract
Paigeite from Kamaishi, Iwate Prefecture, with a composition near to the Fe end-member of ludwigite group, has been described. The mineral, a product of boron metasomatism related with a granodioritic intrusion, is found as fibrous aggregates associated with magnetite, hedenbergite, andradite, phlogopite, pyrrhotite and chalcopyrite in the iron ores of the skarn type. Its X-ray diffraction pattern is very similar to those of minerals of the ludwigite group. Oremicroscopic observations have been made. Chemical analysis gave the following percentages and formula: SiO2 1.16, TiO2 0.11, Fe2O3 29.84, FeO 48.72, MnO 0.62, MgO 1.51, CaO 1.60, Na2O 0.29, B2O3 13.24, CO2 1.14, H2O(+) 0.70, H2O(-) 0.52, S 0.09, Total 99.54; (Fe″, Mg, Mn″) 2Fe′′′BO5.
