In some areas they are covered with a layer of volcanic sand.

He sold his printing equipment to buy 3 kilograms of expensive volcanic sand.

Because of the bay, the region benefits from a mild climate and long beaches covered with dark volcanic sand.

At our next stop, the river was wider and stronger as it flowed over a bed of black volcanic sand.

Not volcanic sand, Russell thought, but he didn't want to argue it.

The beach itself is very rocky with black volcanic sand in spots.

The region is also known for its darker, more volcanic sand.

A few black specks were also present, caused by titanic iron or volcanic sand.

The waves pound fiercely here on the black volcanic sand.

Santorini has volcanic sand in a choice of black or red.