guided tour (1hr) in English 9.30am-5.30pm (dusk in winter) - last admission 1hr before closing
This cavern is home to a purplish variety of fluorite known as Blue John. This semi-precious stone, which has been used since Antiquity, is mainly transformed into jewellery. As part of your visit through the succession of lofty caves, admire the superb mineral colourings and the many limestone formations. You will also learn about the terrible working conditions of the early miners here.