The intricacies of gemstone fraud


As technology marches forward, fraudsters get smarter.

The jewellery industry is a business built on trust, or at least it was in the days before lab testing and hallmarking.

However, despite advances in technology it would seem that the age-old crime of stone fraud is still rife. In fact, according to Julian Boles, founder of the British Gemmological Institute (BGI), modern technology is actually increasing the number of fake gemstones on the market.

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Bowles works with police forces in the UK and Scotland Yard, as well as with retailers throughout the country, to carry out highly sophisticated laboratory testing on gemstones to determine whether they are genuine or not. The BGI is usually called in when there is a dispute between a customer and a retailer or when testing by loupe is not sufficient and there is doubt about whether the stone is genuine or not.

As modern science has progressed, the quality of fake stones has also escalated, and Bowles says that he has noticed an “alarming” rise in the number of people trying to pass simulated stones for real stones at retail jewellers.

“In the old days it was pretty simplistic,” he says. “You looked at it with a microscope and you could see the curved growth lines [used to determine a natural stone from a lab grown]. These days synthetics and treatments are intensely clever.”
According to Bowles, top scientists are paid hundreds of thousands of pounds to work on creating synthetics that can pass for the real thing, particularly in the diamonds field.

With increasingly sophisticated techniques, Bowles advises jewellers to always send stones to organisations such as his to be lab tested before buying from a customer. He goes on to admit that there are even rare occasions that his London-based lab has been unable to determine the origin of a stone and has had to call in experts, such as world-renown Kings College physics professor AT Collins, or have had to borrow very expensive and sophisticated X-Ray equipment owned by universities.

Bowles says that the main threat in the field of diamonds at present is high-pressure high-temperature (HPHT) treatments that are used to improve the colour of diamonds. This method can also be used on synthetic diamonds to make them appear more like natural diamonds.

The process of improving diamonds in this way is not illegal, but it is illegal not to disclose that the process has been applied when selling on the stones. And this is where the problem lies, according to Bowles. “It’s often done legitimately at source but then people might forget to say it’s treated,” he says.

While Bowles is perhaps being more generous to the nature of people than he needs to be by using the word “forget”, he adds that out and out diamond fraud is “a headache”.

HPHT treatments work by filling voids or gaps in the diamond with oxygen or nitrogen to change the molecular structure, but this process will leave a minute trail where the needle has been inserted into the diamond. To cover this up, or any other inclusions, to help the diamond pass for real, the trail is then filled with acid and the diamond is put in a vacuum to take all the air out, leaving the acid to bleach the flaws.

“Technically it is extremely clever, but it’s down right fraud,” sighs Bowles. “It’s like being mugged on the street by scientists. We’re talking about thousands of pounds – it’s as bad as a bank raid. Shops are the key to beating this, retailers need to have stones accredited.”


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