The coast at Portknockie features an intermingling of Cullen quartzite (dating from Lower Dalradian times, 650 million years ago during which time they’ve transformed from sedimentary sandstone through partial volcanic metamorphosis) and the usual Highland psammite and semi-pelite.
The colours in these photos are more or less natural; it was totally stunning to be in the shady cave with the daylight behind and beyond, with these huge colourful boulders to play with.
For a sense of scale: the photos featuring a distant patch of light playing on the sandy pebble floor, well that gap is large enough to walk right through. A veritable cathedral of colour.