Blue JohnCavern

Blue John Cavern sits below Mam Tor on the old road between Castleton and Chapel-en-le-Frith, one of two sites in the area where Blue John stone, a banded form of fluorspar, is still mined in small quantities. The caverns were worked commercially for the ornamental mineral until 1926, when landowner Colonel Broadbent halted extraction to protect newly discovered passages; the site opened to the public as a show cave on 1 April 1935, adapted for visitors by John Royse, whose family had acted as agents for the stone for generations. Guided tours run daily, lasting roughly 45 minutes to an hour, taking in the Waterfall Cavern and the Grand Crystallized Cavern, with old mining equipment left in place along the route. Some of the miners who still work the remaining veins also lead the public tours. The cavern trades as a standalone, privately operated visitor attraction rather than a branch of a larger group, distinct from the other show caves nearby.