Výskyt barytokalcitu na žíle Bt22U, šachta 19, uran-polymetalický revír Příbram (Česká republika)

Publication Type:Journal Article
Year of Publication:2014
Authors:Knížek, F, Škácha, P, Sejkora, J
Journal:Bulletin mineralogicko-petrologického oddělení Národního muzea v Praze
Volume:22
Issue:1
Start Page:42
Pagination:4
ISSN:1804-6495
Keywords:baryte, barytocalcite, calcite, chemical composition, Czech Republic, powder X-ray diffraction data, shaft No. 19, uranium and base-metal ore district Příbram
Abstract:

The rare carbonate of Ca and Ba, barytocalcite, was found in the uranium and base-metal ore district Příbram (Czech Republic) for the first time. Specimens were found in one cavity in the year 1983 on the vein Bt22U, 30 - 32 meters above 17th level of the shaft No. 19. At least two generations of calcite are in association with chalk white, yellowish or pinkish soft to crumbly barytocalcite crystal aggregates which are partially replaced by baryte. Individual barytocalcite crystals are up to 2 mm in size and have glassy lustre. Barytocalcite is monoclinic, space group P21/m, the unit-cell parameters refined from the X-ray powder diffraction data are: a 8.104(3), b 5.241(1), c 6.547(2) Å, β 106.02(2)° and V 267.3(1) Å3. Chemical analysis correspond to the empirical formula Ba0.98Ca1.02(CO3)2 on the basis 6 O apfu.

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