(IDEX Online) - Experts were surprised to find a lab-grown diamond that had been laser-treated to enhance clarity.
It is believed to be the first reported case of an LGD having undergone a treatment associated only with mined stones.
Researchers at the Gemological Science International laboratory in Mumbai, India, found the 4.5-ct stone had been drilled to clean out a black inclusion.
"Diamond growing technology continues to improve and growers are trying to mimic natural diamonds in every possible way" said Nick DelRe, GSI's chief information officer.
The diamond has been cut from top and pavilion and the content of the inclusion had been bleached out with acid.
The remnants of the inclusion strongly resembled a laser drill treatment, generally used enhance a diamond's appearance.
Many gemologists would naturally assume that a drilled diamond was natural, rather than lab-grown.
The lab said: "A hasty and inaccurate conclusion could have been made that the diamond is natural, with the appearance of what seems to be a laser drill channel, since there are no recorded cases of lab-grown diamonds with this treatment, nor would it currently make sense to laser drill these diamonds."