Micro‐Raman spectroscopy applied to the study of inclusions within sapphire

Abstract

The present research concerns the characterization of samples of corundum (Al 2 O 3 ), varieties of sapphire, by micro-Raman spectroscopy. Ten samples of natural corundum from Australia, Madagascar, Sri Lanka, Thailand, Tanzania, and Vietnam were studied. After standard gemmological analysis, micro-Raman analysis was also performed in order to identify mineral inclusions within the sapphire samples and to obtain information on the geological genres of the minerals. Several inclusions were evidenced within the sapphires and identified by Raman spectroscopy thanks to a confocal spectrometer, which allowed detection also below the external surface of the gem. Finally, the Raman spectra are discussed taking into account the provenance of the samples and their optical absorption.

Cause analysis of chatoyancy of sapphires from Shandong, China

“…For example, samples A3 and B3 exhibit typical Raman displacement of a sapphire mainly concentrated at 300-800 cm À1 . 38,39 The samples showed similar spectra with characteristic peaks caused by seven Raman-active vibrations of Al 2 O 3 located at 748, 645, 575, 450, 416, 432, and 378 cm À1 (Fig. 6).…”

Haze in sapphire crystals grown by SAPMAC method

“…5) show that the crystal matrix expresses Raman peaks at shift 378.7 cm -1 , 416.3 cm -1 , 448.1 cm -1 , 577.8 cm -1 , 750.8 cm -1 , 1357.6 cm -1 and 1495 cm -1 . All the peaks except that at shift 1357.6 cm -1 and 1495 cm -1 which correspond to the Raman peaks of C [16,17] are belong to Al 2 O 3 [18]. The Raman peaks in the bubble appear at shift 416.1cm -1 , 576.1cm -1 , 749.0 cm -1 and 1283.2 cm -1 .…”

Raman spectroscopy in art and archaeology

“…A look inside the materials used as precious stones or as cutting tools can be an aid in provenance. This is the case for the sapphire inclusions in the paper by Palanza et al 6 , and those of rock crystal artefacts that enabled Sachanbiński et al 7 to discriminate among different ancient mines in Poland by identifying specific crystals inside rock crystals.…”