Inyoite from Fuka, Okayama Prefecture, Japan

Isao Kusachi, Shoichi Kobayashi, Mitsuo Tanabe, Shigetomo Kishi, Junji Yamakawa

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

Inyoite was found as fissure fillings in calcium borate minerals, which occur as an irregularly shaped body in the crystalline limestone near the gehlenite??spurrite skarns at the Fuka mine, Okayama Prefecture, Japan. Inyoite occurs as aggregates of tabular crystals up to 1 mm wide, and rarely as euhedral crystals up to 0.5 mm wide in fissures of calcium borate minerals such as nifontovite, pentahydroborite, sibirskite and parasibirskite. The fissure fillings are composed only of inyoite. This is the first finding of inyoite in Japan. The type of occurrence is also different from those in many other localities in the world. Electron microprobe and CHNS/O analyses gave the empirical formula Ca 1.99B 5.96O 5.92(OH) 10· 8.08H 2O on the basis of O = 24. The unit cell parameters are a = 10.616(2), b = 12.068(1), c = 8.404(1) Å and β = 114.01(1)°. The mineral is optically biaxial negative with refractive indices α = 1.492, β = 1.506 and γ = 1.517, giving a calculated 2V = 82°. The Vickers microhardness is 91 kg mm -2 (10 g load) and the Mohs hardness number is 2.5. The measured density is 1.875 g cm -3. It is likely that the inyoite at the Fuka mine was formed by a reaction of ground water with calcium borate minerals at a temperature of around 20°C.

Original languageEnglish
Pages (from-to)67-71
Number of pages5
JournalJournal of Mineralogical and Petrological Sciences
Volume99
Issue number2
DOIs
Publication statusPublished - 2004

Fingerprint

borate
Japan
borates
minerals
fissure
calcium
mineral
gehlenite
crystal
limestone
refractive index
ground water
electron probe analysis
microhardness
hardness
crystals
occurrences
refractivity
groundwater
cells

ASJC Scopus subject areas

  • Geophysics
  • Geology

Cite this

Inyoite from Fuka, Okayama Prefecture, Japan. / Kusachi, Isao; Kobayashi, Shoichi; Tanabe, Mitsuo; Kishi, Shigetomo; Yamakawa, Junji.

In: Journal of Mineralogical and Petrological Sciences, Vol. 99, No. 2, 2004, p. 67-71.

Research output: Contribution to journalArticle

Kusachi, Isao ; Kobayashi, Shoichi ; Tanabe, Mitsuo ; Kishi, Shigetomo ; Yamakawa, Junji. / Inyoite from Fuka, Okayama Prefecture, Japan. In: Journal of Mineralogical and Petrological Sciences. 2004 ; Vol. 99, No. 2. pp. 67-71.
@article{c6896fd2748c442aa1194f06dcdd7461,
title = "Inyoite from Fuka, Okayama Prefecture, Japan",
abstract = "Inyoite was found as fissure fillings in calcium borate minerals, which occur as an irregularly shaped body in the crystalline limestone near the gehlenite??spurrite skarns at the Fuka mine, Okayama Prefecture, Japan. Inyoite occurs as aggregates of tabular crystals up to 1 mm wide, and rarely as euhedral crystals up to 0.5 mm wide in fissures of calcium borate minerals such as nifontovite, pentahydroborite, sibirskite and parasibirskite. The fissure fillings are composed only of inyoite. This is the first finding of inyoite in Japan. The type of occurrence is also different from those in many other localities in the world. Electron microprobe and CHNS/O analyses gave the empirical formula Ca 1.99B 5.96O 5.92(OH) 10· 8.08H 2O on the basis of O = 24. The unit cell parameters are a = 10.616(2), b = 12.068(1), c = 8.404(1) {\AA} and β = 114.01(1)°. The mineral is optically biaxial negative with refractive indices α = 1.492, β = 1.506 and γ = 1.517, giving a calculated 2V = 82°. The Vickers microhardness is 91 kg mm -2 (10 g load) and the Mohs hardness number is 2.5. The measured density is 1.875 g cm -3. It is likely that the inyoite at the Fuka mine was formed by a reaction of ground water with calcium borate minerals at a temperature of around 20°C.",
author = "Isao Kusachi and Shoichi Kobayashi and Mitsuo Tanabe and Shigetomo Kishi and Junji Yamakawa",
year = "2004",
doi = "10.2465/jmps.99.67",
language = "English",
volume = "99",
pages = "67--71",
journal = "Journal of Mineralogical and Petrological Sciences",
issn = "1345-6296",
publisher = "Tohoku University",
number = "2",

}

TY - JOUR

T1 - Inyoite from Fuka, Okayama Prefecture, Japan

AU - Kusachi, Isao

AU - Kobayashi, Shoichi

AU - Tanabe, Mitsuo

AU - Kishi, Shigetomo

AU - Yamakawa, Junji

PY - 2004

Y1 - 2004

N2 - Inyoite was found as fissure fillings in calcium borate minerals, which occur as an irregularly shaped body in the crystalline limestone near the gehlenite??spurrite skarns at the Fuka mine, Okayama Prefecture, Japan. Inyoite occurs as aggregates of tabular crystals up to 1 mm wide, and rarely as euhedral crystals up to 0.5 mm wide in fissures of calcium borate minerals such as nifontovite, pentahydroborite, sibirskite and parasibirskite. The fissure fillings are composed only of inyoite. This is the first finding of inyoite in Japan. The type of occurrence is also different from those in many other localities in the world. Electron microprobe and CHNS/O analyses gave the empirical formula Ca 1.99B 5.96O 5.92(OH) 10· 8.08H 2O on the basis of O = 24. The unit cell parameters are a = 10.616(2), b = 12.068(1), c = 8.404(1) Å and β = 114.01(1)°. The mineral is optically biaxial negative with refractive indices α = 1.492, β = 1.506 and γ = 1.517, giving a calculated 2V = 82°. The Vickers microhardness is 91 kg mm -2 (10 g load) and the Mohs hardness number is 2.5. The measured density is 1.875 g cm -3. It is likely that the inyoite at the Fuka mine was formed by a reaction of ground water with calcium borate minerals at a temperature of around 20°C.

AB - Inyoite was found as fissure fillings in calcium borate minerals, which occur as an irregularly shaped body in the crystalline limestone near the gehlenite??spurrite skarns at the Fuka mine, Okayama Prefecture, Japan. Inyoite occurs as aggregates of tabular crystals up to 1 mm wide, and rarely as euhedral crystals up to 0.5 mm wide in fissures of calcium borate minerals such as nifontovite, pentahydroborite, sibirskite and parasibirskite. The fissure fillings are composed only of inyoite. This is the first finding of inyoite in Japan. The type of occurrence is also different from those in many other localities in the world. Electron microprobe and CHNS/O analyses gave the empirical formula Ca 1.99B 5.96O 5.92(OH) 10· 8.08H 2O on the basis of O = 24. The unit cell parameters are a = 10.616(2), b = 12.068(1), c = 8.404(1) Å and β = 114.01(1)°. The mineral is optically biaxial negative with refractive indices α = 1.492, β = 1.506 and γ = 1.517, giving a calculated 2V = 82°. The Vickers microhardness is 91 kg mm -2 (10 g load) and the Mohs hardness number is 2.5. The measured density is 1.875 g cm -3. It is likely that the inyoite at the Fuka mine was formed by a reaction of ground water with calcium borate minerals at a temperature of around 20°C.

UR - http://www.scopus.com/inward/record.url?scp=33845607782&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=33845607782&partnerID=8YFLogxK

U2 - 10.2465/jmps.99.67

DO - 10.2465/jmps.99.67

M3 - Article

VL - 99

SP - 67

EP - 71

JO - Journal of Mineralogical and Petrological Sciences

JF - Journal of Mineralogical and Petrological Sciences

SN - 1345-6296

IS - 2

ER -