Pete Oxford / Tiger tree frog (Hyloscirtus tigrinus) captive, endemic to Ecuador.

Ross Hoddinott / Marbled White butterfly (Melanargia galathea) resting on grass, Dunsdon Nature Reserve, Devon, UK. July

Mark Taylor / 'The Marble Cathedrals' - marble rocks dissolved and sculpted by water. Rio Tranquilo, Chile, March 2010.

Jack Dykinga / Lichen covered rocks at Marble Viewpoint, Kaibab National Forest, Grand Canyon National Park, Arizona, USA

Jack Dykinga / Lichen covered rocks at Marble Viewpoint, Kaibab National Forest, Grand Canyon National Park, Arizona, USA

Erlend Haarberg / Rock formations (of marble and gneiss) 2, with the Engenbreen glacier in the background. Meloy, Nordland, Norway, August 2012.

Erlend Haarberg / Rock formations near Engenbreen glacier, Meloy, Nordland, Norway, August.

Erlend Haarberg / Rock formations near Engenbreen glacier, Meloy, Nordland, Norway, August.

Nick Upton / Cotham marble / Landscape marble boulder, a tough limestone with attractive landscape-like patterns when polished, formed from fossilised cyanobacterial stromatolites, exposed by river action, Lower w...

Adrian Davies / Beech (Fagus) with spalting, or mottling affect caused by White Rot Fungus, newly cut tree, Surrey, April

Franco Banfi / Marble shrimp (Saron sp.) Raja Ampat, Irian Jaya, West Papua, Indonesia, Pacific Ocean

Doug Perrine / Marble cone shell (Conus marmoreus) Restorf Island, Kimbe Bay, New Britain, Papua New Guinea. Bismarck Sea / Western Pacific Ocean (Non-ex).