The iPhone 5 camera does not capture the true nature and intensity of reds and oranges and salmon hues. Especially the earthy pigments, ochers, iron oxides, siennas.
Looking at these rocks as a palette I am reminded of Victoria Finlay's book Color: A Natural History of the Palette. An amazing half history half travel log that takes you on her search across the globe for the origins of pigments. Just as she was color collecting so too am I.