Friday, September 25, 2015

De Beers' DiamondSure - Synthetic Diamonds

Because synthetic diamonds have identical properties to natural diamonds, it is almost impossible to determine a synthetic stone through a visual examination alone.

The difference in the growth process of a synthetic diamond compared to natural diamond can be identified using either cathode luminescence using electrons to highlight the stone's structure, or a camera to view the fluorescence pattern created on the surface of a polished stone with intense short wave ultraviolet light. Most colorless HPHT synthetics show phosphorescence - an afterglow - when the ultraviolet lamps are turned off. An identification can then be made by observing the fluorescence patterns characteristic of near-colorless synthetics.

The DiamondView enables lab staff to view tell-tale growth patterns for synthetic diamonds. The regular striations visible in the middle of this round diamond indicate it is a CVD-grown synthetic.
De Beers is preparing a defense against undisclosed synthetics in the form of a mass-screening device to fast-check melee for synthetics.

The device is in production.

The Gemological Institute of America has developed, and will sell to the trade, a screening device for the detection of lab-grown as well as high-pressure, high-temperature (HPHT) treated diamonds.

Unveiled to members of the trade press in January, the table-top device, called the DiamondCheck, is about the size of a toaster oven and can be used to test diamonds from one point to 10 carats in size.

The machine gives users one of three results about the inserted stone: it is a natural diamond; it is a diamond but should be referred to a lab for further testing because it could be synthetic or treated; or it is non-diamond material such as moissanite or cubic zirconia, though the device does not specify the type of material.

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