This mantelpiece-garniture of plinth-supported urns are of festive wine-krater form enriched with 'Pan' reed-gadroons. A drawing for a closely related urn features in Messrs Boulton and Fothergill's Pattern Book (N. Goodison, Ormolu: The Work of Matthew Boulton, London, 1974, fig. 161, no. L).
Bluejohn, a rare fluorspar deposit from the Castleton area of Derbyshire has been prized since Roman times. However, it was only mined in quantity when the neighbouring spa town of Buxton became fashionable in the mid-18th Century and an industry developed to supply objects to the affluent visitors. The Bluejohn stone was exported in the late 18th Century to France for luxurious objects and its name is a corruption of their appellation 'bleu jaune'.