Crystal chemistry and Raman spectroscopy of momoiite from Japan

Momoiite, a Mn2+– and V3+–dominant member of the garnet group, has been reported from metamorphosed manganese deposits in Japan. Near end–member momoiite (Mn3V2Si3O12) has not yet been found in nature, and the chemical composition of natural momoiite is written as (Mn,Ca)3(V,Al)2Si3O12, which represents intermediate compositions in solid–solution series between spessartine and Mn–rich goldmanite. Single–crystal X–ray diffraction data were...