01335 216 004 Phones Open: 8:30am - 6:00pm
Cart Cart

About Derbyshire Blue John

Blue John is a semi precious gemstone which was first discovered over two thousand years ago by the Romans. Blue John is a rare variety of the mineral Calcium Fluorite, with distinctive, purple, blue and golden yellow banding, which runs through the stone and makes each Blue John gemstone truly unique. There are fourteen known varieties of this beautiful gemstone and for over three decades C W Sellors has maintained a heritage and unrivalled still and craftsmanship in the design and manufacture of finely crafted Blue John jewellery collections.

The origin of the name 'Blue John' is believed to have come from the French 'blue et jaune', meaning 'blue and yellow', which was though have been later abbreviated to 'Blue John'. Steeped in rich history, Blue John has been displayed in stately homes throughout the country for centuries, made world famous by the craftsmanship of Mathew Boulton in the late 18th century. The story goes that Blue John was exported to France where it was used by ormolu workers during the reign of Louis XVI (1774–1791). However, there is no archival records of any Blue John being exported to France, and many of the early ormolu ornaments incorporating Blue John were in fact manufactured by Matthew Boulton of Birmingham in the 1760s.


Discovered over two thousand years ago, the only known deposit of this rare and beautiful natural gemstone occurs in a hillside to the west of Castleton, Hope Valley, Derbyshire, England, opposite the mountain known as 'Mam Tor', often described as the 'Shivering Mountain'. Blue John has only ever been found within the Blue John Cavern and Treak Cliff Cavern in Castleton in Derbyshire. 

Mam Tor reaches a total height of 517m (1,696 ft) located nearby to Castleton in the High Peak of Derbyshire, England. The name 'Mam Tor' means 'mother hill', a name given due to the frequent landslips on its eastern face which have resulted in a multitude of 'mini-hills' beneath it. These landslips are caused by the unstable lower layers of shale, that has since lead to the hill alternative name of the Shivering Mountain. In 1979 the continual battle to maintain the link road between Sheffield and Chapel en le Frith was lost, the road was finally closed as a through route due to the crumbling eastern side of the hill. 


Blue John is Britains rarest mineral first discovered in Castleton, Derbyshire, by the Romans almost two thousand years ago. The Romans settled just three miles from the area in the village of Brough, and is likely that they were prospecting for deposits of lead ore when they struck upon Blue John fluorspar purely by chance. Being keen mineralogists, they would instantly have recognised the outstanding beauty of their find. During this period the romans developed skills along with the machinery to enable them to turn and polish the stone to transform the raw material into beautiful Blue John ornaments and artefacts. During the excavations of Pompeii two vases of Blue John stone were supposedly unearthed, evidence therefore that the Romans not only discovered the stone but also prized the stone for its ornamental value.

Throughout the 19th century and Regency period the Blue John mineral became in very high demand, frequently used for ornamental purposes, to produce exquisite vases, columns, tables and even windows in many of the finest houses in Britain, most notably Buckingham Palace and Chatsworth House, Derbyshire, the home of the Duke and Duchess of Devonshire.

During the first world war, there was a rising need for supplies and machinery to help assist with the ongoing war effort. This meant that fluorspar also became in high demand as flux was often used in blast furnaces. Blue John being a rare form of calcium fluorite was mined purely for this purpose throughout the war period. During this time tons of Blue John material had been extracted and transported to the nearby city of Sheffield, which had quickly growth a reputation worldwide for its steel production, recognised around the world as one of the leading steel producers and became known as the 'Steel City'. Sadly, by this time substantial amounts of material had been extracted from the hillside, leaving many of the recognised Blue John veins in very short supply and in some instances fully worked out, which meant that the larger Blue John pieces required to produce ornamental items had been lost during this period.  

In late 1926, commercial mining for Blue John, as the then land owner, Colonel Broadbent, took steps to preserve and protect the newly found cave passageways. On April 1st 1935, these passageways, caves and caverns, along with the 'old series' mine were opened to the public for the very first time.

Since 1945, the cavern has been in the guardianship of the Harrison family, with only small amounts of Blue John which have been mined out from closed and hidden areas of the cavern 'off the beaten track' since that time. Today Blue John continues to be used to produce stunning unique items of jewellery. Treak Cliff Cavern is one of only two working Blue John mines in the world, with restrictions in place which allow only half a ton per year to be extracted.

To this day C W Sellors continue to specialise in producing fine Blue John Jewellery since 1979. Discover our exclusive collections of Blue John Jewellery available online and throughout our stores.


Blue John which is also known as Derbyshire Fluorspar, is a semi precious gemstone mineral, a unique form of fluorite with distinctive bands of a purple, blue and yellowish colouring, found only in Blue John and Treak Cliff Caverns, Castleton, Derbyshire. Blue John is a heavily crystallised formation and occasionally surface marks can be seen. This is not detrimental to the stone and in fact enhances its individuality. It has been seen that certain specimens of Blue John show signs of fluorescence on exposure to ultraviolet light, but this is the exception rather than the rule.

The gemstone is the most highly prized ornamental variety of Fluor-Spar (Calcium Fluoride), differing from any other variations of flour-spar due to its unique crystal structure, and banded veins of colour which run through the stone. During the 18th and 19th centuries Blue John was mined for its ornamental value, producing exquisite bowls, eggs and goblets. 

Splendid unique specimens of Blue John stone can be found in collections throughout the world. The mines are sadly now largely extinct, however, small veins and nodules of fine quality Blue John stone of sufficient size for jewellery can still be found. 


The Treak Cliff Cavern's mining operations are first thought to have initially taken place between 1745 and 1750, it is widely believed that this mine was the very first 'Blue John stone' mine in the world, which still to this day can be seen in operation as mining continues on a very small scale.

Treak Cliff Cavern remains open to tourists and visitors throughout the year, along with the small mining operation, which takes place during the quieter winter months. Cavern guides often help carry out the mining along with the ongoing Cavern maintenance to help preserve the underground cave during the cold, damp winter months.

The extracted gemstone material is then carefully graded and sorted by hand, before being expertly cut and polished to be transformed into exquisite items of jewellery.


Found only in the caverns deep below the Derbyshire Peak District village of Castleton, the Derbyshire Blue John gemstone is one of the world's rarest minerals. Mining Blue John is essentially done by hand. Blasting is resorted to in only rare exceptional circumstances, as the shock can often disturb the crystalline structure and in some instances has also been known to shock the distinctive colouring and banding out of the stone, rendering the fluor-spar an off white opaque colour and incapable of being worked. It is the unique colouring and banding which adds to the prized value of the stone. 

Often the Fluorspar occurs in veins surrounded by limestone needing a more complex process to remove them. Wedges and crowbars are carefully driven into the bedding plane beneath the deposit before the entire piece can be carefully removed and the true size of the find is only then discovered.

The precise quantities mined in any given year are unknown, but the leases in 18th century restricted output to 20 tons per annum. By 1892, the output is said to have been limited to 3 tons per annum. Today, production is running at approxamately only half a ton per annum, of which is mainly worked and transformed into stunning unique pieces of jewellery.


For many years it had been in doubt as to whether the vein was actually ever in existence. In January 2013, the 'Lost Vein' of Blue John was re-discovered 68 years after the vein had first originally been found. It's exact location was lost in 1945 following the death of the old miner John Royce, but was finally re-discovered by Gary Ridley and John Turner, who continue to oversee the mining and preservation of the Blue John, Treak Cliff Cavern.

The discovery of the lost vein has helped solve one of the longest running mysteries, whilst resurrecting many peoples intriguing love for this truly unique British gemstone. 


In August 2015 the most recent vein of Blue John was uncovered, over 150 years since the last discovery.

The new vein has been named the 'Ridley Vein' after Gary Ridley, the miner who found it whilst attempting a new mining method with a stone chainsaw. The vein was found close to the main tourist route. Gary commented saying that 'Having spotted a small amount of crystallisation near the handrail it was just an easy and convenient place to see how well the saw would cut. I couldn't believe my eyes when within a few minutes I had uncovered a substantial deposit of Blue John unlike any other vein I had ever seen before.'

Vicky Turner, whose family have owned and managed Treak Cliff Cavern since the 1940's, said the Ridley Vein displays 'Swirling patterns of purple and blue', Vicky confirmed that the material uncovered will be turned into decorative bowls and used to produce special collections of jewellery.

Each vein of Blue John has its own colour and unique banding of blue, purple, yellow and white. Historically, there have been fourteen recorded distinctive veins of Blue John including the famous 'Millers Vein', 'Treak Cliff Blue Vein', '5 Vein', '12 Vein' and 'Old Tor Vein'. The newly discovered vein has now entered the record books as variant number 15, named the Ridley vein, having been uncovered by Gary Ridley in august 2015.


Blue John is a semi precious gemstone considered to be one of the rarest minerals in the world, found only within the Treak Cliff Cavern, Castleton, Derbyshire Peak District National Park. Treasured as one of the world’s rarest minerals, each piece of Derbyshire Blue John stone is unique and varied in colour, common veining makes every piece of Blue John jewellery truly special.

Discover our timeless collections of handmade Blue John Jewellery. Exquisite jewellery designs incorporating only the finest quality hand selected Blue John stone. Our team of skilled lapidarists transform each piece of naturally formed Blue John gemstone into elegant jewellery designs. We offer a stunning selection of Blue John Jewellery, including rings, earrings, necklaces and bracelets finished to the highest standard and suitable to be worn for all occasions. Shop the very latest Blue John Jewellery including our beautiful handmade Blue John and Diamond Jewellery

We hand select each individual gemstone to be carefully crafted and transformed into stunning pieces of Sterling Silver, Yellow Gold and White Gold Blue John Jewellery. Precision cut, and polished to perfection, explore the finest British craftsmanship with our handmade gemstone jewellery collections, incorporating locally sourced Blue John, manufactured in our workshop based in Ashbourne, Derbyshire. 

Contact us today to book an appointment in store, or speak with our online concierge team about producing bespoke or custom made items of jewellery. 



Shop our award winning and exclusive collections of Derbyshire Blue John Jewellery. Discover our wide range of Blue John Rings, Blue John Earrings, Blue John Necklaces and Blue John Bracelets, available to buy online and throughout our stores with free UK delivery on all orders.