Peake-o-matic

We visited Treak Cliff Cavern, a mine in the only hill in which Blue John stone is mined. Blue John is a semi-precious mineral with blue and yellow striations. it is reputedly named after the French translation 'bleu jaune', though it has been mined since Roman times. Two vases made of it were found in Pompeii. These pictures don't feature any of the sought-after mineral, just some mineral formations deep inside the caves.