Details

Autor(en) / Beteiligte

• KOBAYASHI, Shoichi
• YUASA, Manami
• TANABE, Mitsuo
• KISHI, Shigetomo
• KUSACHI, Isao

Titel

Vimsite from the Fuka mine, Okayama Prefecture, Japan

Ist Teil von

• Journal of Mineralogical and Petrological Sciences, 2019, Vol.114(5), pp.219-223

Ort / Verlag

Sendai: Japan Association of Mineralogical Sciences

Erscheinungsjahr

2019

Quelle

EZB Electronic Journals Library

Beschreibungen/Notizen

• Vimsite was found as a mass or a veinlet in crystalline limestone associated with gehlenite–spurrite skarns at the Fuka mine, Okayama Prefecture, Japan. Vimsite occurs as colorless to white aggregates of anhedral or prismatic transparent crystals up to 1 mm in length in association with shimazakiite, sibirskite, priceite, uralborite, calciborite, kurchatovite, and calcite. It is also formed as a 0.5 mm wide veinlet. An electron microprobe analysis of vimsite gave an empirical formula (Ca0.993Mg0.009Fe0.003Mn0.001)Σ1.006B1.996O2(OH)4 based on O = 6. The unit cell parameters are a = 10.021(3), b = 9.566(4), c = 4.447(2) Å, β = 91.231 (9)°. The calculated density is 2.523 g cm−3. The Vickers microhardness is 186–206 kg mm−2 (25 g load). It is likely that vimsite from the Fuka mine was formed by subsequent hydrothermal alteration, as with uralborite and priceite, of sibirskite produced by the hydrothermal alteration of shimazakiite.