RapNet


Rapaport News

 

Technology

 
Rapaport Broadcast
Martin Rapaport’s Webinar on Estate Jewelry
October 30 2019

Advanced search
Latest Articles
Videos
Features
News
Mining
Rough Markets
Polished Markets
Manufacturing
Retail

Lab Finds 3ct. Synthetic with Fake Report

CVD diamond also had a forged laser inscription, says China’s National Gemstone Testing Center.
Apr 15, 2018 5:45 AM   By Joshua Freedman
Print Print Facebook Facebook Twitter Twitter Share Share


RAPAPORT... A grading laboratory in China has discovered a synthetic diamond masquerading as a natural stone, complete with a forged inscription and a falsified report.

The National Gemstone Testing Center (NGTC) in the city of Shenzhen received a round-brilliant, 3.1-carat diamond ring, which it subsequently graded as F or G color and VS clarity, it said last week.

However, when gemologists checked the laser-inscription code that was already on the girdle, using an online certificate-verification service, they found the grading report bearing that number was for a natural diamond with similar, but not identical, characteristics. The certificate they saw online was for an H-color, VS1-clarity diamond.

The Chinese lab carried out tests that confirmed the stone in the ring was synthetic, created using chemical vapor deposition (CVD). The inscription and accompanying paper report, purporting to be from an international grading laboratory, were fakes, the NGTC said.

The stone had a type of impurity, known as a “silicon-vacancy center,” that is extremely rare in natural diamonds but common in CVD diamonds, helping the scientists identify its origins. It also had other characteristics that indicated it was synthetic, such as showing green fluorescence under ultra-violet light.

While this was not the first case of its type — the Gemological Institute of America last year found a synthetic diamond with a forged inscription — it is rarer for a Chinese lab to make such a discovery, NGTC noted. It is also one of the larger synthetic diamonds to have cropped up with false credentials to date, the lab added.

“The growth technology of CVD synthetic [diamonds] has been making great progress for decades in [terms] of size, color and clarity,” the lab said. “Recently, the distinct characteristics of the synthetic diamond are becoming less, and it is more difficult to differentiate.”

Images: National Gemstone Testing Center
Tags: Certificate, chemical vapor deposition, cvd, CVD diamond, Gemological Institute of America, grading laboratory, Inscription, Joshua Freedman, lab, National Gemstone Testing Center, NGTC, Rapaport News, synthetic diamond
Similar Articles
GGTLLab Creates Tech for Identifying Stolen Stones
Jun 02, 2019
GGTL Laboratories has developed technology that can match a stolen...
De Beers Opening Blockchain to Industry
Lab-Grown Ban Splits Opinion on Facebook
Comments: (0)  Add comment Add Comment
Arrange Comments Last to First



Call Us: 1-702-893-9400
Member License Agreement   RapNet Trading Rules & Code of Conduct    Privacy Policy  
  
twitter twitter
About Rapaport
Advertise with us