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Licensed Unlicensed Requires Authentication Published by De Gruyter (O) July 28, 2010

Low quartz On the geometry of its structure framework in terms of the directed bond

Abstract

Structurally critical directions, from the point of view of interpreting deformation features in quartz, and their angular relations have been computed from lattice constants and coordinate parameters. The computed values are tabulated, projected and discussed. This in effect amounts to an analysis of the structure in terms of:

  • (1) the directions of lines joining nearest neighbouring unlike nuclei;

  • (2) planes defined by combinations of nearest neighbouring nuclei;

  • (3) the directions of symmetry elements for SiO44− groups; and

  • (4) the angular relations among all these directions and planes.

It is suggested that there are five non-rational potential fracture planes, as measured from the unique axis, at angles of 29° 19′, 47° 38′, 51° 46′, 61° 38′, and 78° 56′. These imperfect cleavages of roughly equal facility are believed to combine to give rise to conchoidal surfaces of fracture. At angles 43° 52′ and 66° 29′ planar fractures should tend to be inhibited. Below the rupture strength, deformation is thought to occur through rotation of SiO44− groups about their axes of [unk] symmetry.

Published Online: 2010-07-28
Published in Print: 1961-11
Downloaded on 19.3.2024 from https://www.degruyter.com/document/doi/10.1524/zkri.1961.116.1-2.83/html
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