Danger Dust

There’s more to beach sand than meets the eye. It has stories to tell about the land, and an epic journey to the sea. That’s because mountains end their lives as sand on beaches.

Over time, mountains erode. The mud, sand, gravel, cobbles and boulders they shed are washed into streams, which come together to form rivers. As they flow down to the sea, all this sediment is ground up and worn down in nature’s version of a rock tumbler.

Big rocks break down into smaller pieces, so most of what reaches the sea is mud. These silt and clay particles are too small to perceive with the naked eye. But you can see individual grains of sand, which are just bigger bits of rock.