Miedziankit z Miedzianki koło Chęcin

Authors

  • Eugenia Gajda

Abstract

MIEDZIANKITE FROM MIEDZIANKA NEAR CHĘCINYSummaryMiedziankite found at Miedzianka near Chęciny, within the Świętokrzyskie Mountains, belongs to a group of sulphur salts, i.e. to the minerals which have regular symmetry and make an isomorphic rank tenantite-tetrahedrite. Goniometrical examinations of the miedziankite crystals allow to determine the merohedrism of faces {12l}, {131}, {123}, and consequently the presence of three twofold axes only. The faces (123), (123), (123), (123) make the right sphenoid. The values of spherical co-ordinates  j and r of the faces here considered do not differ from those characteristic of the regular system. Nevertheless, the symmetry of the miedziankite crystals may be considered orthorhombic.X-ray examinations prove the presence of a superstructure observed in two directions, parallelly to the twofold axes. Dimensions of a characteristic cell of miedziankite are as follows: a = 10.24 A, b = 30.78 A, c = 40.92 A, space group – D12, Z = 96.

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