Sloping mounds of sand in any color of the rainbow extend as far as the eye can see. The brilliant colors are due to the presence of trace minerals in the sand; copper turns the sand turquoise or blue, while iron renders it a rusty red, and sand that is primarily comprised of quartz can be white, pale pink, or purple. Despite the beauty of the dunes, they can be quite dangerous. There is little fresh water to be found, and no shelter should it storm. Furthermore, walking through the sand is difficult. Those few traders and nomads who do traverse the dunes often do so on the backs of horses or camels.