Treak Cliff Cavern
Treak Cliff Cavern is, along with Blue John Cavern nearby, the only show cave in the world with veins of Blue John visible to the public. The Cavern entrance is found halfway up the Treak Cliff on the old Mam Tor road just outside Castleton.
It was discovered by lead miners searching for their elusive ore. Instead they came across a dark mineral which they took to be coal until they extracted it and saw it in full light. It was these miners who sent it to France and who doubtless misheard the French name of Blue Jeune and called it Blue John.
The first half of the Cavern comprises tunnels dug by the miners (and enlarged for our passage) through a huge boulder field. Treak Cliff marks the division between a deeper limestone basin (where the Hope Valley lies now) and a shallower lagoon above) Huge boulders would have rolled down this cliff line becoming lodge and 'cemented' together to form the current steep hillside.
However, there is much more to Treak Cliff Cavern than artificial tunnels. As the miners dug deeper, they broke through into a natural cave passage, widened by water of millions of years. Here they found a magnificent collection of stalactites and stalagmites - a veritable fairy's treasure trove!
Treak Cliff Cavern is still an active mine. Blue John is dug from hidden veins every winter to supply the shops and jewellers with the ingredients to make the following year's necklaces and earrings.
Treak Cliff Cavern incidentally serves a fabulous cup of tea. Water is collected from the bottom of the cavern and pumped up to the cafe above. Filtered by tons of limestone above, it's great stuff!