A RARE TURQUOISE-GLAZED HEXAGONAL BISCUIT BRUSHPOT, BITONGKangxi Elegantly potted with six straight sides rising from a stepped foot with six bracket-feet, rising to a flat-lipped mouth rim, covered with a lustrous turquoise-blue glaze with a 'fish-roe' crackle, save the base. 14.6cm (5 3/4in) high. 清康熙 綠松石釉六角筆筒 Provenance: Heliot Fils, Rue de Berlin, Paris (label) S. Marchant & Son, London, 12 June 1996 Published and Illustrated: S.Marsh, Brushpots: A Collector's View , Hong Kong, 2020, pp.192-193. 來源：Heliot Fils, Rue de Berlin, 巴黎（標簽） 倫敦古董商 S. Marchant & Son，1996年6月12日 展覽與錄著：S.Marsh, 《Brushpots: A Collector's View》，香港，2020年，頁192-193 The present lot has a lustrous turquoise-blue glaze. Turquoise glazes were occasionally used during the Tang dynasty on earthenware tomb figures and by the 12th century the glaze was used at kilns associated with tile-making; turquoise glazes can be seen on Jin dynasty (1115-1234) Cizhou stonewares. While turquoise glazes were applied to Jingdezhen porcelains in the Yuan and Ming dynasties, they did note to prominence on porcelain until the Qing dynasty. This low-fired alkaline glaze was made by mixing saltpetre (potassium nitrate), quartz and copper powder. The turquoise glaze is highly fluxed, and is quite runny during firing so it tends to pool attractively in the various indentations of the design as it cools. The glaze would be applied and fired after the porcelain vessel had had an initial 'biscuit' firing. The base is covered in a thin clear glaze and shows an imprint of the fabric on which the pot stood before the feet were applied. Turquoise-glazed porcelain vessels continued from the Kangxi to Yongzheng and Qianlong reigns. See a turquoise glazed meiping vase, incised Kangxi six-character mark and of the period, which was sold at London, 12 May 2016, lot 67.