A pink and green tourmaline 'Twin cats' pendant, 18th-19th century. Photo Christie's Image Ltd 2014.

The green section of the stone is carved to depict one cat, with the other lying alongside it carved from the pink section. The two-tone stone contains some cloudy inclusions. 1 ? in. (4.2 cm.) wide. Estimate £6,000 – £8,000 ($10,086 - $13,448)

Christie's. FINE CHINESE CERAMICS AND WORKS OF ART, 13 May 2014, London, King Street - http://www.christies.com/