Chemical Studies of Minerals Containing Rarer Elements from the Far East District. LXI. Yttrofluorite from Suishoyama, Kawamatamachi, Fukushima Prefecture, Japan

Abstract
A very rare yttrium mineral, yttrofluorite, from granite pegmatite found at Suishoyama, Fukushima Prefecture, was studied. Chemical analysis: Ca 35.50%, Σ Rare earths 18.84%, Mg 0.42%, Fe 0.34%, Al 0.15%, Mn 0.08%, F (remainder) 44.67%. Cell constant calculated from the X-ray powder data: a0=5.500 Å. Specific gravity: 3.51 (measured), 3.62 (calculated). Refractive index: n=1.454. The distribution pattern of lanthanide elements studied by the X-ray fluorescent method disclosed that the mineral is poor in cerium group lanthanide, rich in yttrium group with maxima at dysprosium and erbium. The mineral occurs as aggregates of small crystals in spessartine garnet embeded in large crystals of feldspars.