Published November 1981 | Version v1
Journal article

Symmetry and twinning in boltwoodite

  • 1. Institute of Mineralogy and Crystallography, Technical University of West Berlin

Description

The authors give the results of an x-ray diffraction and chemical analysis of boltwoodite from Namibia. Chemical analysis revealed that as well as potassium there was a considerable amount of sodium; thus one may speak of sodium boltwoodite with the molecular ratio K2O:Na2O = 2 : 1. The potassium and sodium are partly replaced by H3O. The idealized formula is (K,Na)/sub 2-x/(H2O)/sub x/ x [UO2SiO4] x H2O; the symmetry is monoclinic, the space group being C2/sub 2h/ = P21/m, with a = 6.65 A, b = 7.07 A, c = 7.11 A, β = 105030', Z = 2. The acicular crystals are elongated along [010] with a very pronounced cleavage in 001. The cleavage plane is (101). The mineral bears a very marked resemblance to kasolite

Additional details

Publishing Information

Journal Title
Sov. Phys. - Crystallogr.
Journal Volume
26
Journal Issue
6
Series
Sov. Phys. - Crystallogr.
Journal Page Range
732-735
ISSN
0038-5638