However, this green sand isn't actually sand at all ... Cinder cones are composed of dark-colored igneous rocks like basalt, diabase, and peridotite found near hot spots on tectonic plates ...

These falls, known as foss in Icelandic, range in volume from the most powerful waterfall in Europe, Dettifoss, to those that plunge into swirling blue-green pools, cascade down black basalt ...