Roweite from the Fuka mine, Takahashi, Okayama, Japan

Abstract

A few reddish brown roweites (up to 0.2 mm in size) were found in calcium borate minerals such as uralborite, bultfonteinite, fluorite, calcite near outcrop of shimazakiite at the Fuka mine, Okayama Prefecture, Japan. Roweite was first described by Berman and Gonyer (1937) from an occurrence in Franklin, New Jersey, USA. This is the first finding of roweite in Japan. Electron microprobe analysis gave the empirical formula Ca_2.007(Mn_1.405Fe_0.331 Mg_0.177Zn_0.037Co_0.004)_Σ1.953B_4.021O_6.984(OH)_6.016 on the basis of O=13. The unit cell parameters are a=9.08(5) b=13.32(6), c=8.23(4)Å.