This big chunk of calcite has lovely swirls of pattern on its chalcedony skin. Not tumbled or polished, this Scottish rock came from down in South Ayrshire. It has been in the rock room since God knows when. I picked it up to prove to someone that you could find calcite in salt water.... So it must have been on a beach cleaning trip.

We have a deal with the land. It gives us rocks and we take away the rubbish.

This rick has a mix of sedimentary and volcanic stuff in it. It is incredibly unique in its patterns. It might arguably be an agate. I never sliced it because it has to nice an outer edge.