The Unique Blue John Stone - Found only in Castleton....

Chemically, Blue John stone is a variety of fluorspar - calcium fluoride. It differs from other fluorspars because it appears in definite bands of different colour - blue, white, yellow and occasionally red.

All Blue John is found under one hill to the west of Castleton village. It occurs in veins of an average 3 inches thick or in nodules that line the walls of cavities in the surrounding carboniferous limestone. Blue John is often called "the rarest natural formation in the British Isles". The stone was discovered probably 2000 years ago and probably by accident. The mines of Castleton were originally natural caverns that were opened up in Roman times to mine lead and other ores. The Romans would have immediately appreciated the beauty of the stone and mined it for use in ornamentation.

There are a number of references to the stone in Roman literature. The philosopher Pliny refers to beautiful "Vasa Myrrhene... The principal colours were purple and white, disposed in undulating bands, and usually separated by a third band, in which the two colours being mixed, assumed the tint of flame". (Pliny, Liber 37. Cap 2.). Pliny also relates the story of a Roman consul who so desired a piece of Blue John that he bit a piece off one of the vases so that he could keep it! (It is sometimes quite brittle!)

The Romans, so it is recorded, so highly prized ornaments made from Blue John that astronomical prices were paid for them. A large ornament made of Blue John would change hands for around $24,000. Pliny recorded that a man named Petronius paid 300 talents ($110,000) for one particularly fine piece which he broke up believing that the tyrannical Nero had condemned him to death in order to obtain it! Nero himself paid 6000 sistertia ($190,000) for another piece.

Two Blue John vases were found during the excavations of Pompeii.

Sadly, mention of Blue John in historical documents disappears after the Roman era although presumably mining of the mineral still took place.

It is not until the 1700s that there is documentary evidence of an employee of Earl Fitzwilliam of Wentworth, near Sheffield, collecting various examples of Blue John and incorporating them in a rockery at Wentworth stately home. A craftsman who worked in marble, Mr John Platt, saw the rockery, took two pieces and worked them into salt cellars. These were seen by a Mr How of Castleton who directed the craftsman in the direction of Castleton to obtain further samples to be worked.

Further craftsmen have used Blue John over the years but the most famous is Robert Adam who incorporated the stone into his tables and mantelpieces, many of which grace the stately homes of England and are considered priceless.