Blue John Cavern
Blue John Cavern is home to eight of the fourteen known varieties of Blue John stone, a beautiful and ornamental fluor-spar. The mineral has been mined here for centuries and continues to be in the winter months. Miners armed with picks and shovels pursue the stone deep in the mine workings, where it is found in veins in the limestone or loose in the clay beds lining the passageways. Guided tours are conducted throughout the cave system at short regular intervals. Each tour lasts approximately 45 minutes to 1 hour during which time a series of magnificent natural water-worn caverns are seen. Blue John can be seen in its natural state along with stalactites, stalagmites and huge caverns. See their webiste for times -- www.bluejohn-cavern.co.uk/ (Castleton, England)
