The 'flawless' 118.28 carat unmounted oval brilliant-cut stone was mined and cut in South Africa two years ago and is the largest and most significant such stone graded by the Gemological Institute of America.
It sold for HK$212m (£17.9m) hammer on October 7, beating the previous record set at a premium-inclusive $26.7m (£16.6m) by Christie's in Geneva in May this year.
