A rare large grey and brown jade 'duck' brushwasher, 17th-18th century. photo Bonhams

The unusual waterpot carved as a duck standing on its webbed feet, with its head turned towards the left holding a millet sprig in its beak, with the wings spread over the body around the oval opening, the stone of grey-green tone with brown inclusions with the upper section and wings turning into dark brown. 16.6cm (6½in) wide. Estimate: £4,000 - 6,000, HK$ 47,000 - 71,000

Footnote: The superb craftsmanship of the carver is demonstrated in the overall design, use of the stone's colours and careful balancing of the large receptacle on the two webbed feet. Compare a related pale green jade duck vessel, similarly balanced on its feet, from the Qing Court Collection, illustrated in The Complete Collection of Treasures of the Palace Museum: Jadeware (II), Beijing, 2008, pl.204.

Bonhams. Fine Chinese Art, 13 May 2010. New Bond Street www.bonhams.com