Exceptional and very rare English Derbyshire blue john vase clock. The main body is polished from one large piece of 'blue john' of distinctive colouration. Ormolu swan neck handles and acanthus leaf mounts bisect the marmo nero belgio base slips with the 'blue john top surmounted with an ormolu pineapple finial. The French movement with annular dial, lever escapement& bell striking the hours and halves. Circa 1860-80. Height 41 cms.