MONOCLINIC FERROMAGNESIAN OXIBORATES OF HULSITE ISOMORPHIC SERIES

摘要

Chemical composition, crystallographic parameters, morphology, optic and physical properties, typical mineral associations have been studied for hulsite series oxiborates from Northern Yakutia and Karelia mineral deposits. X-ray structural and thermic analyses allow to consider more than one variants of possible isomorphous substitutions. Generalization of obtained results with available data of published literature confirms the existence of a continuous isomorphic row encompassing monoclinic tin-rich Fe-Mg oxiborates of the hulsite series from their magnesian variety to ferrous one.