Why Liwa Is Red
The red of the world's tallest dunes isn't a fact about the sand — it's a record of everywhere the sand has been. A drowned sea, an ice-age wind and a buried green Arabia, all pressed into a single colour.
Everyone knows why Liwa is red: iron in the sand. It's true the way "the Gulf is white to reflect heat" is true — the first sentence of a much longer story. The red is a microscopically thin coat of rust on grains of clear quartz, and where those grains came from is almost impossible to picture from the dunes: the floor of a sea that no longer exists, lifted grain by grain and stacked three hundred metres high.