Charlie Ross heads to the Peak District and goes underground in search of one of the rarest semi-precious minerals in the world, Blue John. Back on terra firma, he finds out how it’s made into exquisite jewellery and ornaments.

The teams are also hoping to unearth some hidden gems at an antiques centre in Elsecar, South Yorkshire. Guided by Izzie Balmer, siblings in red Katie and Nathan spot a signed cricket bat, but they aren’t bowled over by the price. Shopping with the blues, married couple Gill and Dave, is David Harper. They pick up an old hoe, but can’t decide if it would rake in a profit. In Derby, it’s all to play for as auctioneer Sean Devitt rallies the bidders - but which team will clinch victory? Show less