Characterization of emeralds by micro‐Raman spectroscopy

Abstract

In recent years, the use of Raman spectroscopy as a gemological tool has largely increased, in particular in the conservation science field where a non-destructive and contactless identification is required. In this work, we show the large amount of information which is possible to obtain with Raman analysis on one of the most important gems, emerald, the green variety of beryl. In particular, 14 not certified faceted emeralds have been studied by means of a standard micro-Raman spectrometer, allowing also the identification of some fakes (garnet, glass, and quartz). All the emerald gems have been fully characterized from the vibrational point of view. In particular, the high frequency spectrum, in the OH region, has been exploited to estimate the amount of alkali ions present in the channels of the crystalline structure. In addition, solid and fluid inclusions have been identified and were useful to hypothesize the provenance of the mineral. The shape and position of the characteristic laser-induced luminescence of chromium ions have helped to better define the origin of the gems

Laser-induced REE3+ photoluminescence of selected accessory minerals — An “advantageous artefact” in Raman spectroscopy

“…The most common field of application of Raman spectroscopy is the identification of mineral phases and components of geological samples on the basis of spectral fingerprint-characteristics. Examples include the fields of gemmology (e.g., Fritsch et al, 2004;Jasinevicius, 2009;Bersani and Lottici, 2010;Bersani et al, 2014), archaeometry and cultural heritage (e.g., Edwards et al, 2000;Smith, 2006;Vandenabeele et al, 2007;Ropret et al, 2010), high-pressure petrology (e.g., Korsakov et al, 2005;Stähle et al, 2008;Marschall et al, 2009), planetary mineralogy (e.g., Wang et al, 1995;Sharma et al, 2003;Wang et al, 2004;Popp and Schmitt, 2004;Bozlee et al, 2005;Blacksberg et al, 2010), environmental mineralogy (e.g., Das and Hendry, 2011), palaeontology (e.g., Schopf et al, 2002;Bernard et al, 2007;Chen et al, 2007), biomineralogy (e.g., Li et al, 2013;Pasteris et al, 2014), and many other disciplines. Furthermore, Earth scientists have become increasingly interested in the application of the hyperspectral Raman-mapping technique.…”

Microstructural, Raman, EPMA and X-ray Tomographic Study of the Odisha's Beryl (Emerald) Sample

“…Emerald grew in contact with schist rocks usually contain more alkali ions than those coming from classical granitic pegmatite. Therefore, for 'non-schist type' emeralds, the intensity of 3608 cm -1 bands should be higher than that of the band at 3598 cm -1 [4].…”

Raman Spectroscopy of cultural heritage Materials: Overview of Applications and New Frontiers in Instrumentation, Sampling Modalities, and Data Processing

“…[22,23,157] to precious stones selected for their aesthetic value (Lapis Lazuli, jade, nephrite, etc.) [56,72,82,155], fossilised resins (amber, copal, etc.)…”