New York-based gemological lab, AG&J, recently received a large batch of allegedly natural diamond melee, however, testing revealed that more than 5 percent of the batch was synthetic diamonds.
The client who submitted the diamonds claims the lot was purchased
from a well-known trade source, with whom he had a long-standing
business relationship. He had no idea synthetics were mixed in the lot.
With permission from their client, AG&J reports that a batch
consisting of 4,566 round, full-cut diamonds weighing a total of 56
carats, ranging in size from 0.7-2.5mm, color ranging from fancy intense
to vivid yellow with some brownish modifier, and a clarity range from
VS to SI, was submitted to the lab at the end of December 2012.
Using their proprietary melee testing system, which analyzes each
individual diamond, and not just a sampling, AG&J identified
243-HPHT grown synthetic diamonds. The remaining batch was natural and
Dusan Simic, the CEO of AG&J, believed that the data collected
points to all the synthetic diamonds coming from one source, created to
purposefully commit fraud.
“It was surprising that only four of the 243 synthetic diamonds
showed weak magnetic properties, which are the results of metallic
inclusions,” said Simic. “In my opinion, this indicates that the
synthetic stones were not mixed into the batch accidentally.
Non-magnetic diamonds were chosen on purpose because checking for
magnetism is one of the quick, low-tech ways to screen melee for
The recent findings confirm the necessity in checking melee diamonds
for synthetics, treatments and imitations. Simic stated, “It is crucial
to check every single stone within a batch. Random screening is not
enough. If the end consumer is purchasing jewelry with synthetic
diamonds, believing they are natural, then the trade has not done its
due diligence in ensuring the proper identity of diamonds traded and
sold. Both our ethical obligation and reputation is in question if
diamond melee is not screened.”
The AG&J (Analytical Gemology & Jewelry) Laboratory
specializes in the identification of diamonds and their treatments.
Seasoned in research and development, the lab concentrates on finding
new identification procedures and consulting in HPHT and APHT treatment
and technology. Responding to the trade’s concern of rapidly growing
occurrences of synthetic and treated diamonds mixed in natural batches,
and in mounted jewelry, AG&J developed a system for batch testing
melee accurately in a cost-effective way. The system is based on
internationally accepted diamond identification methods, such as: Raman
spectroscopy, absorbance measurement in the UV-VIS-NIR range, and FTIR
AG&J provides melee-testing services, starting at $2 per stone.
To further address this growing issue, the lab is currently developing a
system to identify stones mounted in jewelry. “We hope to have the
first prototype of this system working by mid-2013,” said Simic.