Thursday, May 24, 2012

Trade Warning Issued IGI

Large volumes of undisclosed man-made diamonds are believed to have entered the market after several hundred stones were sent to laboratories in Antwerp and Mumbai to be certified as natural diamonds.

· Mostly F to J Color, Clarity VVS – VS. Internal characteristics were feathers,
pinpoints, small dark crystals. The inclusions are strikingly similar to natural
inclusions, hence, microscopic observation is insufficient to conclude.
· Sizes ranged from 0.30 ct to 0.70 ct.

· Polish, Symmetry and Cut were either “Excellent” or “Very Good”.

· Bruted or faceted girdles.

· They were all type IIa and were referred as such by DiamondSure.

· When tested using DiamondPlus all the synthetics gave a “refer CVD” result.

· When viewed in DiamondView they showed bluish green fluorescence and blue
phosphorescence, with characteristic striations.

· The synthetics showed moderately strong photoluminescence from H3 and
nitrogen-vacancy optical centres (zero-phonon lines at 503 nm and 575/637 nm
· They also exhibited photoluminescence at 737 nm that is attributed to siliconvacancy
· Absence of any laser inscription.


CVD synthetic diamonds, diamonds triple treated to avoid detection and diamonds recut to match higher grade GIA reports being traded without disclosure. Kudos to IGI for detecting and exposing  CVDs. We advise buyers to require “Natural  Untreated Diamonds” be included on all invoices. Rapaport trade Alert!

1 comment:

  1. DCLA receives on average one treated diamond per week for certification. These treatment range from Fracture filled, laser drilled all the way to irradiated and Synthetic stones. The origin of the diamond and the question, "Did the Jeweller or dealer knowingly submitted a treated diamond" is not always clear. Well after 11 years in Australia I would like to think not. but I would not bet on it.


Note: Only a member of this blog may post a comment.