Advanced Search

GIA Spots Natural Diamond with CVD Blue Layer

May 4, 2017 4:14 AM   By Rapaport News
Comment Comment Email Email Print Print Facebook Facebook Twitter Twitter Share Share

The Gemological Institute of America (GIA) has found a natural diamond with a synthetic coating that tints it blue – and has warned that more such hybrids might be on the market.

The 0.33-carat stone, which had been graded fancy blue, had a thin layer of lab-grown diamond on it, created using chemical vapor deposition (CVD), the GIA explained in a lab note this week. It was the GIA’s first such discovery.

Gemologists at the GIA’s New York lab noticed a number of unusual characteristics that gave away the diamond’s synthetic coloring. The stone contained both nitrogen and boron defects — a rare combination. They also found it was a mixed type Ia and IIb diamond, another highly uncommon scenario. Analysis using the DiamondView imaging machine showed the diamond itself had characteristics of a natural stone, but the top layer bore signs of being manmade.

While the GIA had never before found a synthetic overgrowth on a natural diamond with a fancy-color grade, the lab warned that there were probably more cases out there undiscovered.

“Identification of colored diamonds should be performed very carefully by looking for unusual characteristics, such as a straight boundary line associated with an interface plane, and fluorescence zones with sharp edges in DiamondView images,” the GIA said in the note. “Examination of this fancy-colored composite diamond indicated that similar challenges could exist for colorless and near-colorless diamonds.”
Tags: chemical vapor deposition, cvd, fancy-color diamonds, GIA, Natural Diamond, Rapaport News, synthetic coating, Synthetic diamonds, Synthetics
Similar Articles
Comments: (0)  Add comment Add Comment
Arrange Comments Last to First
© Copyright 1978-2020 by Rapaport USA Inc. All rights reserved. Index®, RapNet®, Rapaport®, PriceGrid™, Diamonds.Net™, and JNS®; are registered TradeMarks.
While the information presented is from sources we believe reliable, we do not guarantee the accuracy or validity of any information presented by Rapaport or the views expressed by users of our internet service.