One particular cave down in Hope Valley, Castleton, might be considered by some to be slightly unusual. It is a show cave, where tourists can go and be guided around to see some of the mysteries of the Earth. That is, during the summer it serves as an exhibition, but during winter, it’s an active mine. Indeed, the miners look for semi-precious mineral all winter long, looking for so-called Blue John or Derbyshire Spar metals, but when summer comes, they remove their workers’ uniforms, and instead become the tour guides.
The cave is believed to have been created by Romans many centuries ago, and back then the Blue John and other minerals were used to create vases, some of which are still preserved in museums to this day. There were stories in Castleton about Blue John vases, and those probably come from this very cave.
While there is no confirmation about the rumours, the mine itself is very ancient and has been mined for many centuries, and to this day, is still popular and valuable. The stones and ornaments found inside of them can still be used to create jewellery and are worth their weight in silver. It recently became even more popular as fashion designers started privileging alternate types of stones.
The point of the cave tours during summer is twofold, first being an educational activity, where people can go in and learn about what miners do and their work environment, and second it brings some extra income to the region. The cave itself is kept illuminated and maintained so that visitors can get a good sight of what goes on inside, and the guides explain how each type of rock was formed.
Fossilised remains of various animals remain and can be clearly seen during the visit, and a souvenir shop at the exit is stocked with minerals from the mine itself. These are bright yellow and blue stones that can be used in the confection of many items, and which always bring in a good price.