Blue John Fluorite
General Information
History
Blue John, occasionally referred to as Derbyshire Spar, is a rare stone found in only one known locality and is particularly close at heart to Eramun due to this locality being close to home for one of our supporters. This mineral, a colour banded form of fluorspar, has been for used for hundreds of years. Throughout the 18th century this beautiful stone was widely seen in the houses of the nobility as everything from ornamental vases to columns created for some of the finest houses of the time, such as Chatsworth.
During World War I fluorspar was in great demand as a flux in blast furnaces so Blue John was mined only for this purpose which unfortunately meant during this time that a lot of ornamental stone was lost during this period.
Geography
Found only in Castleton in the Derbyshire Peak District and is now only mined in two mines in the entire world - Treak Cliff Cavern and Blue John Cavern. For those wanting to get up close and personal you are actually able to visit Treak Cliff Cavern where they offer prospecting and crafting experiences as well as trekking within the cavern (head on over to their website to book your place and avoid missing out).
Both Blue John Cavern and Treak Cliff Cavern are still active mines today with new discoveries still being found. A “lost” vein was rediscovered in Treak Cliff Cavern in 2013 and in 2015 a new vein was discovered close to the tourist route in the same cavern.
Geology
Fluorite is a unique mineral that can be found in a wide spectrum of colours and often forms in hydrothermal (hot water) veins inside other rocks. Interestingly many fluorite crystals will fluoresce under ultraviolet light.
Blue John Fluorite is a banded white and blueish-purple variety of the mineral. Proposed explanations into what has caused this rare stone’s striking colouring include the inclusion of hydrocarbons as the crystal was growing and developing and the inclusion of other elements such as sulphue or manganese, however tests on these crystals have found their structures to be surprisingly pure. Instead, the colour of this stone is believed to be likely the result of radiation damage from the hundreds of millions of years in the ground. It is not known to occur anywhere else in the world and is confined to an area of about 1km³ of the Carboniferous “reef” limestones at Castleton in Derbyshire.
Physical Properties
Appearance
Blue John Fluorite is a beautiful stone with bands of a purple-blue or yellowish colour and white. This rare stone is often found carved into decorative bowls, glasses, vases and more and is often used in jewellery, though due to its softness is not the most suitable stone for any jewellery that will be subject to impact of abrasion.
Moh's Scale
Blue John Fluorite measures a 4 on the Mohs hardness scale making it a relatively soft stone.
Cleaning & Care
Should your Blue John become dirty you can simply clean it by rubbing it lightly with a clean, soft, untreated cloth. Note that this particular stone is somewhat delicate and should avoid contact with silver clearing solutions, perfumes, hairspray etc. and if being worn as jewellery should be removed before swimming or washing.
Crystal Care
Essential Uses
Known as a “genius stone” Blue John Fluorite is the fore-bearer of new information and a stimulant for personal growth. This unique stone brings balance and encourages all forms for trust, both in the universe and in ourselves and our own intuition. Believed to draw off electromagnetic fields this is a great stone for anyone needing a little extra protection in that area. Blue John is a great stone for encouraging clarity of mind and creative intelligence making it handy for anyone needing help focussing, getting their creative juices going or studying.
Our Family Uses
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