Erlend Haarberg / Curved layers of marble and calcium-silicate flowing around mica schist from the Engabreen Glacier, Saltfjellet-Svartisen National Park, Nordland, Norway, September 2006

Philippe Clement / 'Moine schist' rock fragment, part of the Knockan Puzzle at the Knockan Crag National Nature Reserve, Highlands, Scotland, May 2010

Alex Hyde / Alpine toadflax {Linaria alpina} in flower, growing amongst fragments of schist. Austrian Alps, July, altitude 2500 metres

Alex Hyde / Map lichen {Rhizocarpon geographicum} growing on schist boulder, Austrian Alps, altitude 2250 metres

Jack Dykinga / Vishnu's Schist with a polished blue-black sheen, in Inner Gorge, Grand Canyon National Park, Arizona

Konrad Wothe / White marble Sagan-Zaba cliff along shoreline of Lake Baikal showing darker cherry (Black) cliff behind, Pribaikalsky State National Park, Russia

Gerry Ellis / Aerial view of dry Ugab River bed running through Namib Desert, Damaraland, Namibia