Lot 13. A celadon jade ancestor mask, Neolithic period, Shijiahe culture (2500–2000 BC); 6.5 cm . Estimate: 800,000 - 1,000,000 HKD. Lot sold: 1,449,000 HKD. Courtesy Sotheby's. skilfully and subtly worked in relief on one side of the openwork plaque...