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Stellate clusters of zircon needles were observed in this purple-pink morganite. Vertical field of view 0.58 mm.
Source publication
Ten coated jadeite jade samples were investigated by standard gemological testing, DiamondView imaging, confocal laser scanning microscopy, and spectrophotometry, including visible-range, FTIR, and Raman. The light green coating's Mohs hardness and refractive index were much lower than that of uncoated jadeite. Portions of the coating had peeled of...
Citations
... This fluorescence is not consistent with the natural fluorescence behavior of jadeite, that is, none to faint white fluorescence at LW and none at SW (Table 2). In this case, Zhang [161] reported the unusual case of 10 low-quality jades cabochon samples obtained from the Guangzhou gem market. The samples showed a surface coating more similar to a film rather than a classic impregnation, identified by the authors as an organic polymeric coating. ...
... It must be noted that occasionally surface coatings and/or impregnation substances can be applied for the maintenance of cultural heritage samples [162,163]. In fact, coatings are normally applied to gem materials to counterfeit or improve luster and, in some cases, provide a degree of stability [161,164,165]. ...
Featured Application: Based on the data and analytical methodologies reported here, this review can be used as a reference for Green Stones identification and characterization protocols. Moreover , due to the multidisciplinary approach discussed, it can also be considered as an example useful for similar applications.
Abstract: The present review aims to discuss the importance of a multidisciplinary approach in cultural heritage and archaeometry investigations. The analytical methods used to identify and characterize "Green Stones" are discussed as an example. In the present paper, the term Green Stones is applied but not limited to jade materials, which have considerable importance in cultural heritage studies. In fact, archaeological samples made in Green Stones have been discovered worldwide, with many dating back to the Neolithic Age. Moreover, these materials represent an interesting analytical challenge, starting with their nomenclature and, in most cases, the nature of their poly-crystalline samples and their heterogeneity. Indeed, after a brief introduction about the advantages of the non-destructive analytical techniques commonly used for gemstones and cultural heritage samples analyses, the limits of the same have been discussed on the basis of Green Stones applicability. Finally, a multidisciplinary methodology for Green Stones identification and full characterization , which considers materials' heterogeneity and information, has been proposed and based on different references.
During the March 2015 Diamond Show in Basel, Switzerland, a parcel of 6,000 melee-sized colourless diamonds was analysed using the GGTL Diamond Fluorescence Imaging (DFI) Laser+ fluorescence imaging and spectroscopy system. From the entire parcel, one sample stood out clearly with unusual fluorescence colours and distribution, combined with a photoluminescence spectrum that clearly indicated it was a synthetic diamond grown by chemical vapour deposition (CVD).
This article explores the cause of the so-called 'coffee-and-cream' or 'milkand- honey' effect in chatoyant cabochons. This secondary phenomenon, observed in some cat's-eye gems under oblique lighting, is seen as light and dark halves of the stone located on either side of the bright chatoyant 'eye'. The half nearer to the light source appears dark, while the further side is suffused with a creamy brightness. It is demonstrated that the creaminess is caused by reflections from fibres deeper in the stone than those that cause the 'eye', and that it is impossible for such reflections to reach the observer from the side of the stone that is closer to the light source.
