The Gemological Institute of America (GIA) is shining the spotlight on a 10.60-carat fancy vivid blue diamond, which it said is among the rarest fancy colour diamonds it had ever graded.

The pear-shaped, modified-brilliant Xuan Diamond also has an Internally Flawless (IF) clarity. The company said, “Over its 70-year history, GIA has examined nearly every natural blue diamond ever polished – and Xuan stands among the rarest.”

Of all the diamonds submitted to GIA each year, only 2 per cent bear fancy colours. Unmodified blue is among the rarest colours, with few diamonds featuring the saturation necessary to receive the highly coveted fancy vivid grade. 

Paired with an IF clarity and impressive size, Xuan Diamond stands out as “a natural marvel,” GIA said. 

As a type IIB diamond, its intense blue hue is caused by trace amounts of boron, which also gives it the rare ability to conduct electricity. The diamond was likely sourced from the famed Cullinan Mine in South Africa, GIA said, quoting industry experts.