R1: Characterization and description of minerals (Joint Session with The Gemmological Society of Japan)

[R1P-07] Claraite from the Ashio mine, Tochigi prefecture, Japan

*Takefumi NIWA¹, Daisuke Nishio-Hamane², Shouichi Doi¹, Hiroshi Sakurai¹, Numao Atsushi (1. Min. Soc. Nagoya, 2. ISSP, Univ. of Tokyo)

Keywords:Claraite, Ashio mine

Claraite was found from the outcrop on the western side of Mt. Bizentateyama, which is included in the Ashio mine area, in Ashio-cho, Nikko City, Tochigi Prefecture. Various arsenate, sulfate and carbonate minerals are reported from this outcrop. Claraite originated from the Clara mine in Germany and was reported in 1982 with the ideal chemical formula of (Cu,Zn)₃CO₃(OH)₄･4H₂O. Later, several studies added new data, and in 2017 it was redefined as the ideal chemical formula of (Cu,Zn)₁₅(AsO₄)₂(CO₃)₄(SO₄)(OH)₁₄･7H₂O. Claraite from ashio mine is a turquoise-blue, spherical aggregate in the cavity of limonite accompanied Chalcophyllite and brochantite. Under the microscope, it is a lamellar crystal aggregate, and complete cleavage can be confirmed. The Raman spectra are in good agreement with the paper of Biagioni and Orlandi (2017). Although the chemical composition and X-ray diffraction data are incomplete, they are almost consistent with the same paper.