Entrance to the Blue John cavern

The Blue John Cavern is one of the four show caves in Castleton, Derbyshire, England. Image File history File linksMetadata Download high-resolution version (1200x945, 312 KB) Entrance to the Blue John Cavern, near Castleton. ... Image File history File linksMetadata Download high-resolution version (1200x945, 312 KB) Entrance to the Blue John Cavern, near Castleton. ... A show cave is a cave or cave system containing interesting or spectacular features that are easily accessible to the general public. ... This article is about the English village. ... Derbyshire is a county in the East Midlands of England. ... Motto: (French for God and my right) Anthem: God Save the King/Queen Capital London (de facto) Largest city London Official language(s) English (de facto) Unification    - by Athelstan AD 927  Area    - Total 130,395 km² (1st in UK)   50,346 sq mi  Population    - 2006 est. ...

The semi-precious mineral "Blue John" or "Derbyshire Spar" is mined from this cave. Although the cavern works as a show cave, the mineral is still worked here during the winter months. The miners who work the remaining seams act as guides for the underground tours. Octahedral fluorite crystals from New Mexico, USA Fluorite (also called fluor-spar or Blue John) is a mineral composed of calcium fluoride, CaF2. ... Lechuguilla Cave, New Mexico This article is about natural caves; for artificial caves used as dwellings, such as those in north China, see yaodong. ...

Blue John is a blue/purple and white/yellow banded variety of fluorite which locals will tell you is found nowhere else in the world other than this cave and the nearby Treak Cliff Cavern. However, blue fluorite occurs widely throughout Derbyshire and especially in the Ashover and Crich areas. It also occurs where other fluorspar deposits have been mined and so may be found in County Durham (especially Weardale), Cornwall and Wales as well as throughout the world. Indeed, similar banded blue and white/yellow fluorite is now being imported into the UK from China and sold as coming from Castelton. Other deposits of banded blue fluorite occur in Nevada (in the USA) and Southern Iran. The Iranian blue-and-yellow-banded fluorspar has turned up in Roman grave-goods (e.g.as two cups near the Turkish/Syrian border) alongside the Persia to Rome trade route, and this has fed the myth that the Romans exported Blue John from Castleton. They did not. Neither, as often claimed, were two vases made from Castleton Blue John ever excavated at Pompeii. Fluorite (also called fluor-spar) is a mineral composed of calcium fluoride, CaF2. ... Treak Cliff Cavern is of international fame and geological importance. ... Derbyshire is a county in the East Midlands of England. ... Ashover. ... Map sources for Crich at grid reference SK350544 Crich is a village in Derbyshire. ... County Durham is a county in north-east England. ... Weardale is a dale, or valley, of the east side of the Pennines in County Durham, in England. ... Cornwall (Cornish: Kernow) is a county in South West England on the peninsula that lies to the west of the River Tamar. ... This article is about the country. ... This article does not cite its references or sources. ... Pompeii (pom-pay) is a ruined Roman city near modern Naples in the Italian region of Campania, in the territory of the commune of Pompei. ...

In the late 18th century a small local industry was centred on turning vases of Blue John, which might be mounted with ormolu as chimneypiece garnitures. A small amount of the rock is still mined and can be bought as jewellery in local shops. (17th century - 18th century - 19th century - more centuries) As a means of recording the passage of time, the 18th century refers to the century that lasted from 1701 through 1800. ... Chinese vase A vase with a sunflower pattern A modern designed vase The vase is an open container, often used to hold cut flowers. ... It has been suggested that Fireplace mantels be merged into this article or section. ... Amber jewelry in the form of pendants. ...

The name is popularly said to come from the French; bleu-jaune, meaning 'blue-yellow'. It is a fact that some Blue John was indeed sent to France for gilding by the French Ormolu workers of the Louis XVI period. However, they were emulating the pionerring ormolu ornaments of Matthew Boulton of Birmingham who around 1765 called the stone 'Blew John'. It became such a popular base for the ornaments that Boulton tried to lease the whole output of the Castleton mines. Matthew Boulton. ... This article is about the city in England. ... 1765 was a common year starting on Tuesday (see link for calendar). ...

The earliest dated decorative application of Blue John is its use in marble fireplace panels designed by Robert Adam and installed in Kedleston Hall near Derby in 1762.

It was featured on the 2005 TV programme Seven Natural Wonders as one of the wonders of the Midlands. Seven Natural Wonders is a television programme that aired on BBC Two from 3 May to 20 June 2005. ...

External links

• Official site of Blue John Cavern