Veins of a blue-and-yellow banded mineral run through the Derbyshire hillside in Britain’s Peak District, a rare mineral we know today as Blue John. It’s thought to only be found in
Blue John is a variety of fluorite, a mineral composed primarily of calcium fluoride (CaF2). Fluorite belongs to the group of
It displays some diversity within its coloration, being made up of dark blue, pale blue, and yellow bands. The exact source of its midnight-blue hue was debated for a long time, with possible suggestions including radioactive material. However,
Much of the mineral was lost during the First World War when fluorspar became a coveted material as a flux in blast furnaces. Blue John was subsequently mined for this purpose, stripping the region of large veins of the precious stone.
As a beautiful mineral, it’s coveted for jewelry and ornaments, with examples online including goblets and carved panther heads. According to
That said, we are still finding new veins of Blue John in recent times. Back in 2013, a vein that had long been considered “lost” was rediscovered. It was lost following the death of miner John Royce back in 1945, who passed before having a chance to show the landowners at the time the “ins and outs” of Treak Cliff Cavern.
For 68 years, his predecessors failed to find the vein – until January 2013, when a prospecting mission off the Witch’s Cave revealed something interesting hiding beneath some clay.
“There was approximately a metre-length plate of crystals that we worked to clear,” said John Turner, who was present during the search, to
“The next morning we took better lighting into the area along with the big rock drills, but before any drilling took place we had to dig more clay. It was around 1 pm that day we first were able to drill the limestone surrounding the Blue John, by the end of the day’s drilling we had exposed more of the vein we’d ever guessed existed. Then I told Gary about the carpet and wooden batons, he told me of the lost vein of John Royce, and that he had a particular way of covering his work. By the end of the day we had exceptionally beautiful pieces of stone we had not seen at the Treak Cliff for years.”
Again, in 2015, an entirely new vein was discovered by mine manager Gary Ridley, who was testing out a new approach to mining using a stone
BRB, going to fetch our mining chainsaw.