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Contributions to Mineralogy and Petrology

, Volume 39, Issue 2, pp 171–174 | Cite as

Natural boehmite single crystals from Ceylon

  • Th. G. Sahama
  • Martti Lehtinen
  • Pentti Rehtijärvi
Article

Abstract

Single crystals of boehmite, up to 0.1 mm in size, were found in open cavities inside a corundum crystal from the Ratnapura area gem gravels in Ceylon. The unit cell parameters are (X-ray powder pattern): a0=3.695 Å b0=12.212 Å, c0=2.867 Å. The crystallographic orientation is based on X-ray single-crystal precession photographs. The crystals show the faces (it010), (001), (101), and (221). Systematic extinctions agree with the space group Amam. Optical orientation: a∥γ, b∥β, c∥α. Refractive indices are given. The mineral is optically positive with a large optic axial angle.

Keywords

Refractive Index Gravel Mineral Resource Cell Parameter Unit Cell Parameter 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer-Verlag 1973

Authors and Affiliations

  • Th. G. Sahama
    • 1
  • Martti Lehtinen
    • 1
  • Pentti Rehtijärvi
    • 1
  1. 1.Department of GeologyUniversity of HelsinkiFinland

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