The sound of sand reveals its source

LIFT A SHELL from the sand to your ear and everyone knows you can hear the sea. But listen carefully enough and you can hear shells in the sand too. Sand, it turns out, has a signature sound of its own, and now scientists have found a way to tune in.To the untrained eye, one bucket of beach sand looks much like another but mixed into the multitude of microscopic minerals are carbonate chemicals left behind from the shells of long-dead sea creatures such as molluscs. The carbonate concentration varies according to local geology, and Saskia van Ruth, a researcher at Wageningen University in the Netherlands, and her colleagues say this leaves each batch of sand with its own distinctive noise. The results could extend forensic techniques, providing a quick way to determine the source of disputed sand.