What is Sandstone?
[[File:Siccar Point red capstone closeup.jpg|right|thumb|230px|Siccar Point, eroded gently sloping [[Devonian]] [[Old Red Sandstone]] layers forming capping over [[Conglomerate (geology)|conglomerate]] layer and older vertically bedded [[Silurian]] [[greywacke]] rocks.]] [[File:Lower antelope 2 md.jpg|thumb|200px|right|Red sandstone]] '''Sandstone''' is a [[sedimentary rock]]. It is a rock made of compacted [[sand]]. Sand is small grains of [[rocks]] and [[minerals]] (such as [[quartz]] and [[feldspar]]). These are the most common [[mineral]]s in the [[Earth's crust]]. Sandstone which is resistant to [[weathering]] is used for building in many countries. It can be a hard rock. For example, paving slabs can be made out of hard sandstone. Sandstone is converted into [[quartzite]] through heating and pressure. This happens when rocks are squeezed and heated under a [[mountain]] chain.<ref>[[Metamorphic rock]] is formed by [[tectonic]] compression in [[Orogeny|orogenic]] belts.</ref> Sandstone is most likely to be deposited from fast pacing water such as rivers. == Origin == Sandstone forms in two stages. First, layers of sand build up as [[sediment]], either from water or from air (as in a [[desert]]). Then sand particles are compacted by pressure of overlying deposits, and cemented ('glued' together).<ref>The [[geological]] word for this is '[[cementation]]'.</ref> The 'cement' is either [[calcite]] ([[calcium carbonate]]), [[quartz]] ([[silica]]), or [[clay]]. [[Iron oxide]] often makes sandstone a reddish color. == Related pages == * [[Old Red Sandstone]] was laid down in [[Marine biology|marine]] conditions. It is a sort of dirty dark red. [[Devonian]] period. * [[New Red Sandstone]] was laid down in [[desert]] conditions. It is a rock which is fairly bright orange-red in color. [[Permian]] period. == Notes == {{Reflist}} [[Category:Sandstones]]