The Hebridean Island of Iona is largely composed of Lewisian gneiss, a rock which is more typical of the Western Isles and Scotland's far north-west.
This is a detail from a boulder which lies on a beach on the island's west coast, at the evocatively-named 'Bay at the Back of the Ocean'. I was attracted by its pastel colours.
Canon 5D Mark II | ISO100 | 17-40 f/4L @ 40mm | f/11 | 0.1 sec | no filtration
Camas Cùil An t-Sàimh, Iona.