Concerned over alleged sale of synthetic diamonds under the guise of real diamonds, jewellers here have cautioned people against purchasing the precious stones without invoice so as to avoid duplication. According to some traders, there has been a rise in the usage of synthetic diamonds in the market as they are cheaper and look similar to an original diamond. "Today, synthetic diamond costs about 25-30 per cent less than original diamond. In developed markets, people sell it as a synthetic diamond. But, here it is used to replace the original diamond itself," NAC Jewellers, Managing Director, N Anantha Padmanaban told PTI. Elaborating, he said, "in overseas markets, jewellers declare it as synthetic diamond. Also, synthetic diamond in itself is a separate market there. But, here they sell it for the price of an original diamond." Since, a consumer cannot tell the difference between a synthetic and natural diamond, a few reputed jewellers have installed a machine to identify the original diamond, he added. City-based Vummidi Bangaru Jewellers recently unveiled the screening device 'SYNTHdetect' that would be used to identify synthetic diamonds with an aim to create awareness among the public. Vummidi Bangaru Jewellers, Managing Director, Amarendran Vummidi said the device from International Institute of Diamond Grading and Research, a subsidiary of De Beers Group, was imported from the United Kingdom and would be available for the public to check their diamonds. "From the image viewed on a high resolution screen on the device, a diamond can be validated whether it is natural or synthetic", he said. "SYNTHdetect testing provides an ideal platform for customers to check the authenticity of the diamond jewellery," Amarendran Vummidi said. To a query, another city-based jeweller said while purchasing diamond jewellery, a consumer should look for a reputed jeweller and insist on an invoice on purchase. "Today, some consumers insist on purchasing diamond without a bill so that they can avoid paying taxes. By doing that the quality of precious stone gets compromised," he said. To avoid that, customers should insist on invoice which would not only instill fear among traders who sell a synthetic diamond as original diamond but can also be a tool to eliminate such practises, he said. According to a study, the synthetic diamond market in the Asia-Pacific region alone was estimated at USD 7,496 million and was expected to grow at CAGR (compound annual growth rate) 7 per cent till 2023.