This rock is an interesting sedimentary rock specimen. We picked it up in East Lothian back in 2022. We were through in the summer fossil hunting. This was just too interesting to leave behind.
This rock is essentially ironstone. It has formed over generations by compressed layers of iron rich clay squishing together. The top layers are cracked and fragmented. I can see traces of calcite in there but it is mostly worn away or not quite formed yet.
This is an interesting rock which tells a story of years gone past. It has a thumb sized indentation on the back.