Thursday, 11 May 2017

GIA Spots Natural Diamond with CVD Blue Layer - Sierra Leone monster unsold

The Gemological Institute of America (GIA) has found a natural diamond with a synthetic coating that tints it blue – and has warned that more such hybrids might be on the market.

The 0.33-carat stone, which had been graded fancy blue, had a thin layer of lab-grown diamond on it, created using chemical vapor deposition (CVD). It was the GIA’s first such discovery. Analysis using the DiamondView imaging machine showed the diamond itself had characteristics of a natural stone, but the top layer bore signs of being manmade. While the GIA had never before found a synthetic overgrowth on a natural diamond with a fancy-color grade, the lab warned that there were probably more. This fraud, if undetected, would increase the stone's value exponentially.
A much anticipated auction for one of the world's largest diamonds fizzled when the government of Sierra Leone rejected a $7.8 million bid for the rough, egg-sized stone, saying it failed to meet its own valuation. The 709-carat gem is the second largest ever discovered in the West African country.

Sierra Leone is well known for its diamond industry but it has had a chequered history. Diamond sales partly fuelled the country's decade-long civil war when rebel groups exchanged them for weapons.