A Regency Blue John egg or paperweight of good proportions with good colour and veining, set upon a rosewood stand.
Derbyshire Blue John (also known as Derbyshire Spar, or simply Blue John) is a semi-precious mineral, a form of fluorite with bands of a purple-blue or yellowish colour. In the UK it is found only at Blue John Cavern and Treak Cliff Cavern at Castleton in Derbyshire. During the 19th century, it was mined for its ornamental value, and mining continues on a small scale..
There’s,is a wonderful collection in Chatsworth house and another in the Buxton mueseum Derbyshire.
Blue join was highly prized In the upper echelons of society In the late 18 and 9th centuries.