Hostname: page-component-5c6d5d7d68-txr5j Total loading time: 0 Render date: 2024-08-16T16:22:10.567Z Has data issue: false hasContentIssue false
  • English
  • Français

Nifontovite and olshanskyite from Fuka, Okayama Prefecture, Japan

Published online by Cambridge University Press:  05 July 2018

Isao Kusachi  and
Chiyoko Henmi
Isao Kusachi
Affiliation:
Department of Earth Sciences, Faculty of Education, Okayama University, Okayama 700, Japan
Chiyoko Henmi
Affiliation:
Department of Earth Sciences, Faculty of Science, Okayama University, Okayama 700, Japan
Get access Rights & Permissions [Opens in a new window]

Abstract

Nifontovite and olshanskyite, two rare hydrous calcium borate minerals, have been found in crystalline limestone near gehlenite-spurrite skarns at Fuka, Okayama Prefecture. Nifontovite occurs as aggregates of tabular crystals up to 5 cm long and 1.5 cm wide, and rarely as euhedral crystals up to 1 mm long. Olshanskyite occurs as anhedral masses, or as micro-twinned platy crystals up to 1 cm long. Wet chemical analyses give the empirical formulae Ca3.052B5.991O6.038(OH)12·1.96H2O and Ca2.888B3.997(OH)18 on the basis of O = 20 for nifontovite and OH=18 for olshanskyite, respectively. The formulae are consistent with those from type localities.

The X-ray powder data for these minerals were determined with accuracy. The unit cell parameters of nifontovite agree closely with those published previously. X-ray studies show that olshanskyite is triclinic with the possible space group P1̄ or P1 and a = 9.991(5), b = 14.740(11), c = 7.975(3) Å, α = 94.53(4), β = 69.08(3), γ = 112.44(5)° and Z = 3. The density 2.19 g cm−3 (meas.) obtained for olshanskyite agrees with the estimated ideal value 2.31 g cm−3 (calc.). Nifontovite was formed by hydrothermal alteration of an anhydrous borate, and olshanskyite was formed by hydrothermal alteration of nifontovite and the anhydrous borate.

Keywords

nifontoviteolshanskyiteborateskarncrystalline-limestoneFukaJapan
Type
Mineralogy
Information
Mineralogical Magazine , Volume 58 , Issue 391 , June 1994 , pp. 279 - 284
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1994

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Bogomolov, M. A., Nikitina, I. B. and Pertsev, N. N. (1969) Olshanskyite, a new calcium borate. Dokl. Akad. Nauk SSSR (Englis. translation), 184, 1398–401.Google Scholar
Henmi, C. and Kusachi, I. (1992) Clinotobermorite, CasSis(O,OH)ts.5H20, a new mineral from Fuka, Okayama Prefecture, Japan. Mineral. Mag., 56, 353–8.Google Scholar
Kusachi, I., Henmi, C. and Henmi, K. (1984) An oyelite-bearing vein at Fuka, the Town of Bitchu, Okayama Prefecture. d. Japan. Assoc. Min. Petr. Econ. Geol., 79, 267–75.Google Scholar
Kusachi, I., Henmi, C. and Henmi, K. (1989) Afwillite and jennite from Fuka, Okayama Prefecture, Japan. Miner. J., 14, 279–92.Google Scholar
Kusachi, I. (1992) New data on mineralogical properties of henmilite. J. Mineral Soc. Japan, 21, 127-30 (in Japanese).Google Scholar
Malinko, S. V. and Lisitsyn, A. E. (1961) A new boron mineral, nifontovite. DokL Akad. Nauk SSSR, 139, 188-90 (in Russian).Google Scholar
Mitsuda, T., Kusac.hi, I. and Heumi, K. (1972) Mixture of 14 A and 11 J. tobermorite from Fuka, Japan. 26th Gen. Meeting, Cement Assoc. Japan Rev., 47-68.Google Scholar
Nakai, I., Okada, H., Masutomi, K., Koyama, E and Nagashima, K. (1986) Henmilite, Ca2Cu(OH)4[B(OH)4]2, a new mineral from Fuka, Okayama Prefecture, Japan. 1. Occurrence and description. Amer. MineraL, 71, 1234–6.Google Scholar
Shashkin, D. P., Simonov, M. A. and Belov, N. V. (1971) X-ray diffraction study of natural calcium metaborates. Soviet Physics —Crystallography, 16, 186–9.Google Scholar
Yegorov-Tismenko, Yu. K., Simonov, M. A. and Belov, N. V. (1973) Crystal structure of nifontovite Ca3[B303(OH)612.2H20, a natural calcium metaborate. DokL Akad. Nauk SSSR (Englis. translation), 210, 678–81.Google Scholar