Juergen Freund / Aerial of Sturt Stoney Desert with gibber rocks. Gibber rocks are millions of years wind and water weathered chalcedonised sandstone with a hardened crust of soil cemented silica, iron and manganese,...

Floris van Breugel / A rock collector explores piles of fluorescent minerals found in the tailings of the Pacific Tungsten Mine near Darwin, California. The bright colours are caused by fluorescence excited by a shortwave...

Juergen Freund / Close up of Giant Stinging Tree hairs on the leaves (Urticastrum gigas or Dendrocnide excelsa). Contact with the leaves or twigs causes the hollow silica-tipped hairs to penetrate the skin. Australia

Graham Eaton / Tree growing in outcrop of banded Chert, part of the Carboniferous, Pentre Chert formation, Halkyn, Wales, UK, January. The Chert is silicified Limestone, made up in part of micro organism Radiolaria....

Graham Eaton / Outcrop of banded Chert, part of the Carboniferous, Pentre Chert formation, Halkyn, Wales, UK. January. The Chert is silicified Limestone, made up in part of micro organism Radiolaria. This is one of...

Graham Eaton / Outcrop of banded Chert, part of the Carboniferous, Pentre Chert formation, Halkyn, Wales, UK. January. The Chert is silicified Limestone, made up in part of micro organism Radiolaria. This is one of...

Alex Hyde / Photographer heating silica gel over camp fire in rainforest to restore its desiccating properties. The high humidity of the rainforest can fog camera lenses and lead to mould growth, so silica gel is...

Philippe Clement / Chalcedony specimen, cryptocrystalline form of silica, composed of very fine intergrowths of quartz and moganite on white background

Philippe Clement / Jasper specimen, opaque, impure variety of silica on white background

Philippe Clement / Druse of agathe specimen, cryptocrystalline variety of silica, on white background

John Cancalosi / Hertfordshire Puddingstone, a conglomerate of well rounded flint pebbles, embedded in a matrix of fine pale coloured sand, all bound together by hard natural silica cement, Hertfordshire, england

Suzi Eszterhas / Aerial of Kisilidjan Diatomite Plant, Bjarnarflag, used to process Diaomaceous earth, an abrasive substance formed from the silica bodies of diatoms, Lake Myvatn, Iceland, July 2009.

Suzi Eszterhas / Aerial of Kisilidjan Diatomite Plant, Bjarnarflag, used to process Diaomaceous earth, an abrasive substance formed from the silica bodies of diatoms, Lake Myvatn, Iceland, July 2009.

Sean Crane / Monterey Formation of silica-rich rock along Pacific coastline at sunset, Montana De Oro State Park, Los Osos, California

John Cancalosi / Geyserite a opaline silica (Silicon dioxide SiO2) from Yellowstone National Park, Wyoming, USA.

John Cancalosi / Rhyolite, an igneous, volcanic rock, of felsic (silica-rich) composition.

Juergen Freund / Gibber rocks with heat mirage in the background. Gibber rocks are generally angular fragments formed from broken up duricrust, usually silcrete, a hardened crust of soil cemented by silica. South Aus...

Juergen Freund / Gibber rock and pebble littered area of arid or semi-arid country in Australia. The rocks are generally angular fragments formed from broken up duricrust, usually silcrete, a hardened crust of soil ce...

Juergen Freund / Aerial of Sturt Stoney Desert with gibber rocks. Gibber rocks are millions of years wind and water weathered chalcedonised sandstone with a hardened crust of soil cemented silica, iron and manganese,...

Juergen Freund / Aerial of Sturt Stoney Desert with gibber rocks. Gibber rocks are millions of years wind and water weathered chalcedonised sandstone with a hardened crust of soil cemented silica, iron and manganese,...

Juergen Freund / Aerial of Sturt Stoney Desert with gibber rocks. Gibber rocks are millions of years wind and water weathered chalcedonised sandstone with a hardened crust of soil cemented silica, iron and manganese,...

Juergen Freund / Aerial of Sturt Stoney Desert with gibber rocks. Gibber rocks are millions of years wind and water weathered chalcedonised sandstone with a hardened crust of soil cemented silica, iron and manganese,...

Juergen Freund / Aerial of Sturt Stoney Desert with gibber rocks. Gibber rocks are millions of years wind and water weathered chalcedonised sandstone with a hardened crust of soil cemented silica, iron and manganese,...

Juergen Freund / Aerial of Sturt Stoney Desert with gibber rocks. Gibber rocks are millions of years wind and water weathered chalcedonised sandstone with a hardened crust of soil cemented silica, iron and manganese,...

Juergen Freund / Aerial of Sturt Stoney Desert with gibber rocks. Gibber rocks weathered chalcedonised sandstone with a hardened crust of soil cemented silica, iron and manganese, Australia. June 2011

Juergen Freund / Aerial of Sturt Stoney Desert with gibber rocks. Gibber rocks are millions of years wind and water weathered chalcedonised sandstone with a hardened crust of soil cemented silica, iron and manganese,...

Gavin Hellier / The Blue Lagoon, Iceland's most famous tourist attraction is located among the black lava flows outside Reykjavik. The geothermal spa owes its existence to the Svartsengi geothermal power plant powere...

Gavin Hellier / The Blue Lagoon, Iceland's most famous tourist attraction is located among the black lava flows outside Reykjavik. The geothermal spa owes its existence to the Svartsengi geothermal power plant powere...

Floris van Breugel / A wide variety of fluorescent minerals including scheelite (blue/white), calcite (red), silica coatings containing uranyl ions (green), fluorite (pink), and 'desert varnish' (yellow/orange), populate...

Yva Momatiuk & John Eastcott / Mine tailings from years of mining for opals near Coober Pedy, South Australia, Australia

Yva Momatiuk & John Eastcott / Mine tailings from years of mining for opals near Coober Pedy, South Australia, Australia

Adrian Davies / Rock crystals containing Chalcedony, from Cornwall, UK

Juergen Freund / Close up of Giant Stinging Tree stem (Urticastrum gigas or Dendrocnide excelsa). Contact with the leaves or twigs causes the hollow silica-tipped hairs to penetrate the skin. Australia

Juergen Freund / Giant Stinging Tree leaf (Urticastrum gigas or Dendrocnide excelsa). Contact with the leaves or twigs causes the hollow silica-tipped hairs to penetrate the skin. Australia

Juergen Freund / Giant Stinging Tree stem (Urticastrum gigas, also known as Dendrocnide moroides or Dendrocnide excelsa) - close-up of the hollow silica-tipped hairs, Australia

Albert Aanensen / Warbrick Terraces algae and silica ,Wamangu Thermal Area, Rotorua, New Zealand

Steven David Miller / Hamersley Gorge in Karijini Natinal Park, showing tectonic bands of iron and silica. Australia

Mark Taylor / Panoramic view of Silica sand bay. Queensland, Australia.

Albert Aanensen / Waimangu Thermal, silica and algae deposit. Warbrick Terraces, New Zealand

Chien Lee / Caves caused by erosion of silica-based rock, Mount Roraima, Venezuela

Graham Eaton / Opal, hydrated silica, SiO2 nH2O, from Australia

Grant Maslowski / Silica covered rock terraces along the shore at sunrise, Rangatira Island, Chatham Islands, New Zealand. April, 2023.

Tim Laman / Aerial view of white silica sand dune at Cape Flattery, with Cape Bedford visible in the background. Cape York Peninsula, Australia. June 2012

Tim Laman / Aerial view of white silica sand dune at Cape Flattery, with Cape Bedford visible in the background. Cape York Peninsula, Australia. June 2012