Most of my holidays ended up here in Britain, which I regretted at the time, but not as much as now.
I did get to explore places like Cornwall with its wild cliffs, beaches and moors.
The other day I unearthed three pebbles I picked up from beaches at the westernmost tip of Cornwall, where the Atlantic waves race in from America.
They are 'Beach Tin' and are very hard to find these days.
The west of Cornwall is riddled with mineral 'lodes' or veins in the rock and the mines were just shafts dug to follow the them to get at the ore.
The lodes carried on under the sea and the waves broke up the tin ore and then polished it into pebbles which washed up on the shore.
Back in prehistoric times it wasn't so easy to dig mines and Cornish miners used to pick up pebbles like these from the beaches - letting the sea do the work.
The largest pebble is about an inch and a half across;
They are noticeably heavy, as if you can feel the metal inside.
If you google 'cassiterite' you'll find pictures of beautiful black crystals but occasionally you'll find pictures like these and close up you can just make out a crystalline structure.
These pebbles changed the world; ancient people found they could heat them up in a fire and extract a silver metal, which must have seemed like magic.
If they added copper (from Cornwall or North Wales) they ended up with bronze which is harder than anything they'd known before. This brought in the 'bronze age' of tools and axes made of metal instead of stone.
It brought in travel, trade and industry and our world took off because of it.
Here's a couple of pieces of tin;
'Geevor' was a famous tin mine near Cape Cornwall which closed in 1992 and this is a miniature copy of a tin ingot with the mark of the mine on it.
You can see that it has tarnished a little in the air.
The model tin mine lives in a little plastic case which has protected it and even though it's 15 years old it's still shiny.
(a don't stop till you drop production)
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