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Journal of Spectroscopy
Volume 2018, Article ID 8153941, 10 pages
https://doi.org/10.1155/2018/8153941
Research Article

Spectroscopic Characteristics of Treated-Color Natural Diamonds

1State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Beijing, China
2Taidiam Technology (Zhengzhou) Co. Ltd., Zhengzhou, China
3National Gems & Jewelry Technology Administrative Center, Beijing, China

Correspondence should be addressed to Guanghai Shi; nc.ude.bguc@hgihs

Received 15 October 2017; Accepted 28 December 2017; Published 7 March 2018

Academic Editor: Vincenza Crupi

Copyright © 2018 Meili Wang et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

With the increasing availability of treated-color diamonds on the market, their characterization is becoming more and more critical to the jewelry testers and customers. In this investigation, ten color diamonds treated by irradiation (4 pieces), HPHT (3 pieces), and multiprocess (3 pieces) were examined by spectroscopic methods. These diamonds are classified to be type Ia according to their FTIR characteristics. Using microscope and DiamondView, the internal features (such as distinctive color zoning and graphitized inclusions) and complex natural growth structures were observed, which show that the samples are more likely artificially colored natural diamonds. Through photoluminescence spectroscopy, a combination of optical centers was detected, including N-V0 at 575 nm, N-V at 637 nm, H3 at 503 nm, H2 at 986 nm, and GR1 at 741 and 744 nm. Combining with the previous studies, treatment conditions for the studied diamonds were estimated depending on the presence and/or absence of the optical centers. In addition, the coloration mechanism of the samples (blue, green, and red) during the treatment process was also discussed. It is suggested that a number of techniques should be combined in order to make a reliable identification for such diamonds.