US$35m diamond up for grabs in nod to Hong Kong as centre of jewel sales
More traders are bringing in valuable, rare stones to attract super-rich mainland buyers

International experts have given Hong Kong a vote of confidence as a centre of precious jewel sales, despite signs of a cooling economy on the mainland.
Auction house Sotheby's has chosen the city to sell a rare 118-carat diamond in a sale next month and Rio Tinto Diamonds - one of the world's largest suppliers of the stones - is opening a collection preview here today, with both companies aiming at wealthy mainland buyers.
Sotheby's announced it would put what it calls the world's greatest white diamond - which comes from Africa - on the block here on October 7 as part of its regular twice-yearly auction series.
The oval diamond, the size of a small egg, has not been mounted since it was mined and cut two years ago.
The stone, which was discovered in 2011 as a 299-carat rough diamond, has a pre-sale estimate of up to US$35 million.
The preview by Rio Tinto, which owns and operates the Argyle diamond mine in Western Australia, will feature some 64 rare pink, blue and red diamonds. Hong Kong is the final leg of the showcase.