Called Lewisian gneiss, it’s the oldest rock in the UK. It’s found in the northwest extremity of the Scottish mainland and the Western Isles. The gneiss’s new home is in our gardens, where it forms ...
The most commonly encountered geological unit was migmatite, derived from paragneiss with granitic and pegmatitic leucosome. All pegmatitic rocks, quartz veins and sulphide-bearing lithologies ...