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


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.


Refractive Index Gravel Mineral Resource Cell Parameter Unit Cell Parameter 
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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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