Despite grave concerns in the industry over mixing of synthetic lab-grown diamonds with natural diamond parcels, diamantiares have a reason to cheer ahead of the Christmas season.

As per the latest figures issued by Gems and Jewellery Export Promotion Council (GJEPC), India's polished diamond export has increased phenomenally by 56 per cent year on year to $2.15 billion in October. Majority of the diamonds were exported to the United States, Hong Kong and the United Arab Emirates. However, during the first 10 months of the year, India's polished export rose 26 per cent to $18.278 billion.

Interestingly, in the first 10 months of 2013, import of synthetic lab-grown diamonds more than doubled to $62.3 million. Moreover, polished synthetic diamond import also surged 98 per cent to $69 million.

Sources said most of the synthetic lab-grown diamonds are imported from China and sold in the local markets in Surat and Mumbai. The diamantaires purchase synthetic diamonds from the market and then process them clandestinely in the factories located in Surat, Bhavnagar and Amreli.

Later, the polished synthetic diamonds are mixed with the natural diamond parcels to earn huge profit.

A DTC sightholder said, "There has been a phenomenal rise in the import of synthetic lab-grown diamonds this year. This could be attributed to phenomenal increase in rough diamond prices, forcing some to go for cheap synthetic lab-grown diamonds. The problem starts when these synthetic diamonds are mixed with natural diamond parcels without any disclosures."

A GJEPC office-bearer said, "This year's Christmas season has been very good for diamantaires. We are yet to calculate the total polished diamond export in November."