A 0.89-carat diamond-diamond doublet was detected at a diamond laboratory in Antwerp recently, according to an HRD Antwerp news dated 29 September. “It is the first time that a ‘diamond-diamond’ doublet is encountered at HRD Antwerp and therefore it is important to raise awareness of the existence of this technique,” said the report.
Such kind of “deception”, as called by HRD Antwerp, is believed to alter the carat of the stone. “HRD Antwerp explicitly wants to emphasize that any type of diamond doublet is considered ‘treated’ as it is a deception of one of the 4C’s, namely carat. It is for this reason that these doublets will not receive a diamond certificate.”
The report said microscopic analysis of the stone instantly revealed strong internal reflections which are unusual for a diamond. Other evidences include a visible join line in the middle of the faceted girdle, mismatched facets on the girdle above and underneath the join line implying both crown and pavilion were faceted before they were “glued” together, a small band of binding material with different refractive index containing air bubbles found close to the girdle, etc.
Though HRD Antwerp said it is not unlikely that many more diamond doublets might be encountered in the diamond market in the near future, there is no reason to be alarmed as an expert diamond grader will immediately recognize the uncharacteristic internal reflections, even when examining the stone with a magnifier.
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