Description: Derbyshire, early 19th century

The body with an integrated cover and spherical terminus on a spreading circular base, square Ashford marble, and a Blue John plinth.

Blue John is also known as Derbyshire Spar. This material is a semi-precious stone and is considered one of Britain's rarest minerals. It was first discovered by the Romans over two thousand years ago. Blue John is a rare variety of the mineral calcium fluorite with striking streaks of purple, blue, and gold. In the United Kingdom, Blue John is found only in Blue John Cavern and Treak Cliff Cavern in Castleton, Derbyshire. In the 19th century and during the Regency period, Blue John was in high demand and was mined for its decorative value, which was shaped into a variety of ornamental items.