Hostname: page-component-848d4c4894-wg55d Total loading time: 0 Render date: 2024-05-26T11:38:52.382Z Has data issue: false hasContentIssue false
  • English
  • Français

Chemistry, optics, and crystal growth of milarite from Strzegom, Poland

Published online by Cambridge University Press:  05 July 2018

J. Janeczek
J. Janeczek*
Affiliation:
Department of Earth Sciences, Silesian University, Mielczarskiego 60, 41-200 Sosnowiec, Poland
Get access Rights & Permissions [Opens in a new window]

Abstract

Milarite was found in a cavity of a small pegmatitic segregation in association with albite, stilpnomelane and chabazite. Hexagonal, well-shaped crystals of milarite up to 4 mm in length are transparent, pale green in colour, and show bright green cathodoluminescence. The refractive indices are: ω = 1.535, ε = 1.534(Na). D = 2.55 g cm−3. The unit cell dimensions are: a 10.418(4), c 13.817(7) Å, V 1298.7 Å3. Anomalous biaxial sectors and birefringent optical patterns are visible in basal section. 2V varies from 34° in the {0001} sector to 64° in {101} sector. OAP azimuths are related to the external hexagonal symmetry of the crystals. Microprobe analyses of sections perpendicular and parallel to the c-axis revealed a uniform distribution of alkalis, mainly K2O, whereas CaO and Al2O3 contents are slightly higher in prismatic and pyramidal sectors than in the basal sector, but no systematic chemical zoning can be distinguished. The Al2O3 content decreases in the outer zone of the crystal studied due to Be-Al substitution. The average ‘anhydrous’ chemical formula of the Strzegom milarite is: (K0.98Na0.01)Ca1.93Mn0.02(Be2.16Al0.93)(Si12O30). Infra-red data indicate the presence of H2O molecules in the milarite. Internal growth structures of the crystals indicate rhythmic fluctuations of the growth rate resulting in an internal strain, inducing anomalous optical patterns. HRTEM study did not reveal any significant distortion of the milarite lattice.

Keywords

milaritecrystal growthStrzegomPoland
Type
Mineralogy
Information
Mineralogical Magazine , Volume 50 , Issue 356 , June 1986 , pp. 271 - 277
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1986

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

Akizuki, M. (1981) Am. Mineral, 66, 403-9.Google Scholar
Armbruster, T., and Bloss, F.D. (1981) Contrib. Mineral. Petro, 77, 332-6.CrossRefGoogle Scholar
Bakanin, V.V., Balko, V.P., and Solovyeva, L.P. (1974) Sov. Phys. Crystallogr, 19, 460-2.Google Scholar
Černy, P., Hawthorne, F.C. and Jarosewich, E. (1980) Can. Mineral, 18, 41-57.Google Scholar
Chistyakova, M.B., Osolodkina, G.A., and Razmanova, Z.P. (1964) Dokl. Akad. Nauk SSS, 159, 1305-8.Google Scholar
Chukhrov, F.V., ed. (1981) Mineraly, Nauka, Moscow, 3, part 2, 143-50.Google Scholar
Foord, E.E., and Mills, B.A. (1978) Am. Mineral, 63, 316-25.Google Scholar
Goldman, D.S. and Rossman, G.R. (1978. Ibid. 63, 490-8.Google Scholar
Hügi, T., and Röwe, D. (1970) Schweiz. Mineral. Petrog. Mitt, 50, 445-80.Google Scholar
Janeczek, J. (1984) Przeglqd Geo, 3, 165-7.Google Scholar
Oftedal, I., and Saebö, P. C. (1965) Norsk Geol. Tidsskr, 45, 171-5.Google Scholar
Pouliot, G., Trudel, P. Valiquett, G., and Samso, P. (1984) Can. Mineral, 22, 453-64.Google Scholar
Sandomirskij, P.A., Simonov, M.A., and Belov, N.V. (1977) Soviet Phys. Dokl, 22, 453-64.Google Scholar
Scandale, E., Lucchesi, S., and Graziani, G. (1984) Phys. Chem. Minerals, 11, 60-6.CrossRefGoogle Scholar