GIA Spots Second Natural Diamond with Lab-Grown Layer

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PinkDiamond
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GIA Spots Second Natural Diamond with Lab-Grown Layer

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Well, here's another one, so someone's coating diamonds with a CVD coating. Good thing it was submitted so we know this is going on, and remember; you never know what good magnification can reveal, so always inspect gems carefully, and from every angle. ;)

GIA Spots Second Natural Diamond with Lab-Grown Layer
By Michelle Graff
michelle.graff@nationaljeweler.com
May 22, 2019


Image
Gemological Institute of America researchers said the gray and blue components from the lab-grown layer of this diamond combined with the yellow from the natural substrate to create the color, fancy grayish-greenish blue. (Photo credit: Robison McMurtry)

"Carlsbad, Calif.—GIA researchers recently spotted a second natural diamond with a lab-grown layer that added weight and improved the color, and warned that it could mean the trade will see more of these kind of composites.

According to an article by Troy Ardon and Garrett McElhenny in the spring 2019 edition of “Gems & Gemology,” the presence of both boron- and nitrogen-related defects—which are rarely seen together in natural diamonds—tipped them off there was something unusual about the stone.

The DiamondView fluorescence image of the diamond—a 0.64-carat fancy grayish-greenish blue cushion modified brilliant—showed a blue hue caused by the “cape” peak (nitrogen defect) and natural growth features.

The crown image, however, revealed a greenish-blue color common to boron-bearing diamonds and the dislocation patterns typically seen in diamonds grown using the chemical-vapor deposition (CVD) process.

In addition, a side view shows a distinct layer between the natural substrate and the CVD-grown portion of the stone.

Image
This image shows the line of demarcation between the natural diamond and the CVD-grown layer. (Photo credit: Garrett McElhenny)

“These two distinct fluorescence patterns—the greenish-blue from the CVD layer and the darker blue from the naturally grown layer—prove that a layer of CVD synthetic diamond was grown on a natural substrate,” the article states.

A similar diamond, ... "

https://www.nationaljeweler.com/diamond ... rown-layer
PinkDiamond
ISG Registered Gemologist


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