Micro-Raman spectroscopy of gem-quality chrysoprase from the Biga-Canakkale region of Turkey

HATİPOĞLU M., Oren U., KİBİCİ Y.

JOURNAL OF AFRICAN EARTH SCIENCES, vol.61, no.4, pp.273-285, 2011 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 61 Issue: 4
  • Publication Date: 2011
  • Doi Number: 10.1016/j.jafrearsci.2011.08.002
  • Journal Name: JOURNAL OF AFRICAN EARTH SCIENCES
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.273-285
  • Keywords: Chrysoprase, Chalcedonic-quartz, Dispersive confocal micro-Raman spectroscopy (DC mu RS), Biga-Canakkale region, Turkey, CRYSTAL-STRUCTURE, SILICA, QUARTZ, VARIETIES, MINERALS, MOGANITE, SPECTRA, ORIGIN
  • Dokuz Eylül University Affiliated: Yes

Abstract

The commercial quantities of gem-quality dark green chrysoprase are found as the fracture fillings covered with a weathering crust in the silicified serpentinites throughout the border of a metamorphic zone in the Biga-Canakkale region of Turkey. However, the green-stained opaque quartz materials are also present in the same deposit, but these materials are common and in low-demand according to chrysoprase in terms of gemmological importance. Thus, it is necessary to distinguish these two similar materials from each other non-destructively. In addition, all chrysoprase roughs in this deposit also have alpha-quartz and moganite inclusions. Accordingly, dispersive (visible) confocal micro-Raman spectroscopy (DC mu RS) allows us to distinguish clearly the chalcedonic-quartz silica phase (fibrous quartz (chalcedony)) from the crystalline-quartz silica phase (fine-grained alpha-quartz) in the case of both quartz inclusions in the chrysoprase material and itself of the green-stained quartz material in the same deposit.