Mettle of miners crystal clear at the jewel trove

Slitt Mine, Weardale, County Durham Miners descended a shaft almost 600ft deep to bring up the lead ore, labouring in a candlelit labyrinth

Our children called this place the jewel mine when we first brought them here 30 years ago to collect fluorspar from the bed of Middlehope burn. There was still glittering under the water as I climbed down the bank this week to pick up a few crystals.

Depending on the purity, the crystals vary from pink to purple. One piece, larger than the rest, seemed unusually heavy. When I turned it over I could see that it was fused to a chunk of galena, or lead sulphide, the raw material for products such as bullets and the lead flashing that goes on church roofs.