Portal:Derbyshire/Selected article/21
Treak Cliff Cavern is a show cave near Castleton in Derbyshire, England. It is part of the Castleton Site of Special Scientific Interest and one of only two sites where the ornamental mineral Blue John (vein pictured) is still excavated (the other is the nearby Blue John Cavern). None of the Blue John which can be seen by visitors is now mined. This is part of an agreement with English Nature. However it is still mined from other ares of the cavern but the quantities are not large. The mineral that is mined is converted into saleable items like bowls, jewellery and ornaments.