Looking for Blue John

Exploring caverns and mines in the Peak District seeking a special kind of rock.

Treak Cliff Cavern

The southern half of the Peak District is known as the White Peak because of its limestone geology. As limestone is porous, the area is riddled with caves and mines.

In years past metals such as lead were mined here; there is some evidence that even the Romans mined here. In more recent centuries the caves have been mined for Blue John stone.

Treak Cliff Cavern
A vein of Blue John in the Treak Cliff Cavern

Never heard of Blue John? That might be because this is the only place on earth where it is found.

Blue John is found in hues of purple, white and, predominately, blue and yellow. One explanation of the name ‘Blue John’ is that it derived from the French Bleu Jeune which translates as ‘Blue Yellow’. The semi-precious stone was transported to France during the reign of Louis XVI where it got its name which was then mangled by the English (nothing new there) into ‘Blue John’.

Treak Cliff Cavern
Blue and yellow ‘Blue John’ stone

The Blue John is found under Treak Cliff Hill by the village of Castleton and the caverns can be accessed from either side of the hill.

On one side is the Blue John Cavern which I visited a while ago. This week I visited the Treak Cliff Cavern on the other side of the hill.

Both caverns are only accessible on a guided tour. The tours last about 45 minutes and run regularly throughout the day almost every day of the year.

From the car park we walked halfway up the hill to get to the entrance. The views that spread out below are gorgeous.

view from Treak Cliff Cavern

Whilst waiting for the tour to start we got the chance to polish a bit of Blue John. It was a lot easier than I’d imagined. The small piece of stone was dunked in water and then rubbed in a circular motion on a piece of soft sandpaper stuck to a bit of wood. I was amazed at how quickly it became smooth and shiny.

polishing stone at Treak Cliff Cavern
Polishing Blue John is so easy even a 7 yr old can do it.

The tour guide started by leading us along a long narrow passageway and down steps to reach the first cavern. He pointed out veins of Blue John and switched off the lights so we could see what it would have been like for the early miners who had only candlelight to see by. Once away from the entrance, there is no natural light at all.

Treak Cliff Cavern
Candlelight – how the cavern would have looked to the Victorian miners.

Much of the Blue John has been mined already, though some mining still goes on and jewellery made from the stone can be bought in Castleton’s gift shops.

Treak Cliff Cavern

Last year, Gary Ridley, manager and miner discovered a new vein of Blue John whilst trying out a new mining technique. This is the first new vein to have been discovered in over 150 years and the vein has been called the Ridley Vein after him.

Treak Cliff Cavern
This pillar of Blue John can’t be mined as it’s holding the roof up.

The new vein is the fifteenth known vein. Each vein has a name such as Miller’s Vein and Odin’s Vein and each is unique in the way its colours are arrayed.

Treak Cliff Cavern
Colourful flowstone

As well as the Blue John, our guide also pointed out the many stalactites, stalagmites and flowstone formations. The colours of the flowstone are wonderful.

Treak Cliff Cavern

As are the swirls on the roof of the cavern formed by whirlpools hundreds of thousands of years ago.

Treak Cliff Cavern
Looking up at the swirls and colours formed by an ancient whirlpool.

We also saw fossils. These were formed 330 million years ago when what is now the cavern was part of the seabed near the equator.

Treak Cliff Cavern

At the furthest point into the cavern of our tour the guide pointed out a blue tank. It’s much bigger than it looks in this photo and holds the water that is fed into it from different parts of the cavern. This fulfills two purposes; it helps with the drainage of the cavern and it is used to make tea and coffee in the cafe. As the water has filtered through layers of rock it is really pure.

Treak Cliff Cavern

I did try to taste some that was dripping from the roof, but just ended up with a very wet face.

We exited the cavern at the end of the tour higher up the hill and walked back down to the entrance. We had planned on getting a cup of tea, but as it was quite busy went into Castleton instead.

So I never got to try cave water.

I’ll just have to go back.

Have you been in any unusual caves or mines? Share in the comments below.

Author: Anne

Join me in my journey to live a life less boring, one challenge at a time. Author of the forthcoming book 'Walking the Kungsleden: One Woman's Solo Wander Through the Swedish Arctic'.

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