The most recognised images of the Coloured Sands of Rainbow Beach show bands of red and orange colours along the steep sand dune cliffs. The coloured sands formed as a result of water moving through the sand mass, depositing iron-oxide minerals and organic matter in coloured bands. Here is a conglomerate of coloured sand "pebbles" on a large boulder that must have fallen onto the beach. We're not sure how these different coloured pebbles grouped and reformed into a conglomerate like this. Double-click on the photo to see it up close.