Diamond weighing 5.19 carats cut "cushion" and the size of 10.04 × 9.44 × 6.18 mm was introduced in Hong Kong GIA laboratory for certification. Stone was not declared a synthetic diamond. Using standard screening and testing processes, the laboratory has identified it as a synthetic diamond grown by CVD. After studying the stone was made GIA Identification Report, and the girdle of the diamond was deposited number of the report with the words' grown in the laboratory, "according to the GIA rules for undeclared synthetic stones.
This is the biggest synthetic the CVD-diamond GIA laboratory investigated to date, and the largest of which has ever been reported in the jewelry industry. Diamond has a color index equivalent degree J and the color scale parameter purity equivalent VS2, which is comparable to high-quality natural counterpart. It is important to note that the internal inclusions, such as "needle" and "cloud", to appear natural. Under the microscope also clearly be seen a strong grain and cracks on the site. It should be noted that black inclusions, often contained in synthetic diamonds, were not detected in the CVD-sample, which could be mistakenly identified as natural only on the basis of examination under a microscope. Thus, this case highlights the importance of using advanced spectroscopic instruments as well as conventional gemological techniques to ensure accurate identification.
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