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The Up Close event included a workshop on synthetic diamond detection
The Up Close event included a workshop on synthetic diamond detection

Jewellers get up-close with synthetic and treated diamonds

The Australian jewellery industry recently had the opportunity to examine a rare selection of synthetic diamonds as part of a workshop held in an effort to stay ahead of the controversy surrounding undisclosed lab-created stones.

Branko Deljanin, president and head gemmologist of CGL-GRS Swiss Canadian Gemlab, travelled to Australia earlier this month to educate retailers, manufacturing jewellers and suppliers about the increasing number of synthetic and treated diamonds in the market.

Deljanin – who has almost 30 years’ experience in standard and advanced gemmological testing, diamond grading and research – conducted a number of practical sessions for the education event, Up Close, which was organised by the National Council of Jewellery Valuers (NCJV) and held from 15 April to 21 April.

Branko Deljanin, CGL-GRS Swiss Canadian Gemlab president and head gemmologist
Branko Deljanin, CGL-GRS Swiss Canadian Gemlab president and head gemmologist

Jewellers attending Deljanin’s ‘beginner’ workshop were taught how to screen for type II diamonds and identify different synthetics using portable instruments. The gemmologist also discussed the CPF (Cross Polarised Filters) method that he developed as a way for jewellery retailers, valuers and suppliers to screen diamond types and identify synthetics.

The international jewellery industry has recently experienced a number of controversies concerning undisclosed synthetic and treated stones. Deljanin noted an increased number of coloured and colourless synthetic diamonds appearing in the market over the past decade. He urged jewellers to check the origin of small, near-colourless or yellow and pink diamonds that were bought in India and Hong Kong because these parcels could be ‘salted’ with laboratory-grown diamonds.

“It is important to screen parcels of melee diamonds and larger stones for possible synthetic origin,” he said. “Visually, natural and synthetic diamonds can look very similar when comparing size, cut, colour and clarity, but their commercial values differ significantly in coloured diamonds – 50–60 per cent discount for synthetic – and somewhat less in colourless diamonds – 25–30 per cent discount for synthetic – highlighting the importance of detection.”

A more in-depth technical workshop was also conducted, whereby a detailed analysis was given on how to separate different types of stones using a microscope and one piece of low-cost standard gemmological equipment.

Attendees used the simple technique to identify synthetic Carbon Vapour Deposition (CVD) grown and High Pressure High Temperature (HPHT) grown diamonds.

Commenting on the topics raised during this education session, Debra Haigh of Haigh’s Jewellers in Hervey Bay, said, “It was interesting to realise just how much CVD material is now in the market and how we can expect more and more of all types of synthetic diamonds across our desks.”

Other industry issues such as gemstone treatments and the subsequent effects on marketability were also highlighted during the event by a number of international and local gemmologists.

Additional presentations included: The Influence of Country of Origin Reports by Dr Cigdem Lule from Gemworld International; Changing Faces of Jade by Singaporean-based gemmologist Tay Thye Sun; and Diamond Grading Games: The Search for Consumer Confidence by Melbourne-based Garry Holloway.

The Up Close event, which was said to have received positive industry feedback, was held in Sydney and featured six workshops and a two-day conference.

Monday, 27 May, 2019 12:57am
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