Gabbro, Isle of Skye

The Cuillin Hills on Skye are well known by rock climbers – the coarse, crystalline rock provides excellent grip. These mountains are made of gabbro, a dark, coarse-grained igneous rock.

The coarse grain size shows that the gabbro crystallised slowly, deep underground. It was probably intruded deep beneath a volcano that erupted around 50 million years ago.

The rocks have been cut into sharp ridges and mountain peaks, with deep U-shaped valleys now flooded by the sea, like the loch in the foreground. This scenery is typical of land that has been carved out by glaciers.