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Takedaite, a new mineral from Fuka, Okayama Prefecture, Japan

Published online by Cambridge University Press:  05 July 2018

I. Kusachi ,
C. Henmi  and
S. Kobayashi
I. Kusachi
Affiliation:
Department of Earth Sciences, Faculty of Education, Okayama University, Okayama 700, Japan
C. Henmi
Affiliation:
Department of Earth Sciences, Faculty of Science, Okayama University, Okayama 700, Japan
S. Kobayashi
Affiliation:
Department of Earth Sciences, Faculty of Science, Okayama University of Science, Okayama 700, Japan
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Abstract

Takedaite, Ca3B2O6, has been found in crystalline limestone near gehlenite−spurrite skarns at Fuka, Okayama Prefecture. It occurs as aggregates of granular crystals up to 0.8 mm long and 0.3 mm wide. The mineral is associated with nifontovite, olshanskyite, pentahydroborite, frolovite, sibirskite, calcite and an unidentified mineral, is white or pale gray, and has a vitreous luster. Takedaite is trigonal with space group of Rc, a = 8.638(1), c = 11.850(2)Å, Z = 6. The strongest lines in the X-ray powder pattern [d in A(I)(hkl)] are 2.915(100)(113), 1.895(75)(223), 2.756(61)(104), 2.493(44)(300), 2.044(21) (214,131), 2.160(19)(220), 1.976(18)(006), 1.549(12)(306). The Vickers microhardness is 478 kg mm−2 and the Mohs hardness 4.5. The density is 3.10(2) g cm−3 (meas.) and 3.11 g cm−3 (calc.). Wet chemical analyses give the values CaO 71.13%, B2O3 28.41%, ig. loss 0.14%, and total 99.68%. The empirical formula calculated on the basis of O = 6 is Ca3.053B1.965O6, with the simplified formula of Ca3B2O6.

Keywords

takedaitenew mineralborateFukaJapan
Type
Mineralogy
Information
Mineralogical Magazine , Volume 59 , Issue 396 , September 1995 , pp. 549 - 552
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1995

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References

Fletcher, B.L., Stevenson, J.R. and Whitaker, A. (1970) Phase equilibria in the system CaO-MgO-B2O3 at 900°C. J. Amer. Ceram. Soc, 53, 95–7.CrossRefGoogle Scholar
Henmi, C, Kusachi, I., Henmi, K., Sabine, P.A. and Young, B.R. (1973) A new mineral bicchulite, the natural analogue of gehlenite hydrate, from Fuka, Okayama Prefecture, Japan and Carneal, County Antrim, Northern Ireland. Miner. J., 7, 243–51.CrossRefGoogle Scholar
Henmi, C, Kusachi, I., Kawahara, A. and Henmi, K. (1977) Fukalite, a new calcium carbonate silicate hydrate mineral. Miner. J., 8, 374–81.CrossRefGoogle Scholar
Henmi, K., Kusachi, I. and Henmi, C. (1975) Rankinite and kilchoanite from Fuka, the Town of Bitchu, Okayama Prefecture. J. Mineral. Soc. Japan., 12, 205-14 (in Japanese).Google Scholar
Kusachi, I. and Henmi, C. (1994) Nifontovite and olshanskyite from Fuka, Okayama Prefecture, Japan. Mineral. Mag., 58, 279–84.CrossRefGoogle Scholar
Kusachi, I., Henmi, C. and Henmi, K. (1984) An oyelite-bearing vein at Fuka, the Town of Bitchu, Okayama Prefecture. J. Japan. Assoc. Min. Petr. Econ. Geol., 79, 267–75.CrossRefGoogle Scholar
Majling, J., Figusch, V., Hanic, F., Wiglasz, V. and Corba, J. (1974) Crystal data and thermal expansion of tricalciumborate. Mater. Res. Bull, 9, 1379–82.CrossRefGoogle Scholar
Schafer, U.L. (1968) Synthese und rontgenographische untersuchung der borate 3CaOB2O3,2CaOB2O3 und 2CaOB2O3H2O. Neues Jahrb. Mineral. Mh., 75-80.Google Scholar
Schuckmann, W. (1969) Zur kristallstruktur des calcium-borates Ca3(BO3)2. Neues Jahrb. Mineral. Mh., 142-4.Google Scholar
Suzuki, K. and Hira, I. (1970) Study on the system of 2CaOSiO2-3CaOB2O3 . Yogyo Kyokai Shi, 78, 189–95.CrossRefGoogle Scholar
Tulgar, H.E. (1972) X-ray data of the compounds CaO-2B2O3-CaOB2O3, 2CaOB2O3 and 3CaO-B2O3 . Istanbul Tek. Univ. Bull., 25, 22–30.Google Scholar
van der Voort, D., De Rijk, J.M.E., van Doom, R. and Blasse, G. (1992) Luminescence of rare-earth ions in Ca3(BO3)2 . Mater. Chem. Phys., 31, 333–9.CrossRefGoogle Scholar
Vegas, A. (1985) New description of the Ca3(BO3)2structure. Ada Cryst., C41, 1689–90.Google Scholar
Vegas, A., Cano, F.H. and Garcia-Blanco, S. (1975). The crystal structure of calcium orthoborate: a redetermination. Ada Cryst., B31, 1416–9.Google Scholar
Watanabe, T. (1939) Kotoit, ein neues gesteinsbildendes magnesiumborat. Min. Petr. Mitt., 50, 441–63.Google Scholar
Watanabe, T., Kato, A., Matsumoto, T. and Ito, J. (1963) Jimboite, Mn3(BO3)2, a new mineral from the Kaso mine, Tochigi Prefecture, Japan. Proc. Japan Acad., 39, 170–5.CrossRefGoogle Scholar
Weir, C.E. and Schroeder, R.A. (1964) Infrared spectra of the crystalline inorganic borates. J. Res. Natl. Bur. Stand., 68A, 465–87.CrossRefGoogle ScholarPubMed