Sample of Lewisian Gneiss
Gairloch Museum

This rock may look ordinary at first glance, but it is actually a sample of one of the oldest rocks in the world – and certainly the oldest in Scotland.  

Formed three billion years ago, Lewisian Gneiss forms the basement rock for the coastal strip on which Gairloch is situated, as well as the Outer Hebrides, from which it takes its name. Over millennia, this area experienced numerous geological upheavals and now helps us to understand periods of intense volcanic activity, when Europe began to split from North America.