Much of the Snowdonia National Park is made of metamorphic rock. The landscape bears the sign of quarrying for slate at Llanberis and Ffestiniog. The old slate quarries are a tourist attraction, and some have very hard and serious rock climbs.

The hard metamorphic rock forms upland areas, and the action of glacial erosion has produced many superb cliffs for climbing, including this one, Clogwyn du'r Arddu on the flank of Snowdon.

route "Astral Stroll" Cornwall
climber: Tim Banton

I got scared on this route and we never finished it! Astral Stroll is a long traverse above the sea on very hard metamorphic rock.

Notice the bands of white rock - a mineral called quartz formed as the rock was metamorphosed by great heat and pressure. Superheated steam was forced through cracks in the rock. As the vapour cooled, the quartz was formed.

Climbers are an important source of revenue for this part of Cornwall, especially out of the holiday season.