• journal_title：The Canadian Mineralogist
• Contributor：Benjamin Rondeau ; Emmanuel Fritsch ; Pierre Lefevre ; Michel Guiraud ; André-Mathieu Fransolet ; Yves Lulzac
• Publisher：Mineralogical Association of Canada
• Date：2006-
• Format：text/html
• Language：en
• Identifier：10.2113/gscanmin.44.5.1109
• journal_abbrev：Can Mineral
• issn：0008-4476
• volume：44
• issue：5
• firstpage：1109
• section：Articles

In order to obtain a more accurate method of identification of minerals of the amblygonite – montebrasite series, and particularly of gemstones cut from these minerals, we undertook an investigation by Raman spectroscopy, which is known to be a non-destructive method. Therefore, nine rough minerals and gemstones of the amblygonite–montebrasite series were analyzed by Raman spectroscopy, X-ray diffraction, infrared absorption spectroscopy, and the gemological properties (density and indices of refraction) of seven faceted gemstones were measured. Firstly, the Raman signal seems to be a good indicator of the fluorine content in the specimens, and thus useful for an accurate identification. Three peaks evolve significantly as F content increases: from 599 to 604 cm⁻¹, from 1056 to 1066 cm⁻¹ and from 3379 to 3348 cm⁻¹. Also, the FWMH of the peak around 3370 cm⁻¹ increases from 11 to 57 cm⁻¹ as F content increases. Secondly, we found that all faceted gemstones studied herein consist of montebrasite and not amblygonite as usually claimed by gemstones traders.