London-listed Petra Diamonds has announced the final sale process for its 39.34 ct exceptional Type IIb blue diamond, which was recovered at the Cullinan mine, in South Africa.
The company will showcase the diamond in Antwerp from June 15 to 18, in Dubai on June 22 and 23, in Hong Kong on June 29 and 30 and in New York from July 7 to 9.
The tender on Petra’s online bidding platform will close on July 12.
The Cullinan mine is renowned as a source of large, high-quality gem diamonds, including rare blue diamonds.
Petra recently sold a collection of five blue diamonds called the Letlapa Tala Collection for $40-million.
It is believed the blue colour of the diamond is produced by the presence of the trace element boron within the stone’s carbon structure during its formation deep within the Earth’s mantle.
The company says high-quality blue diamonds command the highest values, with Petra’s Blue Moon of Josephine diamond, cut from a 29 ct rough blue diamond, having sold for $48.5-million in 2015.
This translates to a price of $4-million per carat, or $20-million per gram, which remains the world record price per carat ever paid for a diamond.