Editing Sandstone (section)

===Cement===
Cement is what binds the siliciclastic framework grains together. Cement is a secondary mineral that forms after deposition and during burial of the sandstone.<ref name="boggs-2006-119-135"/> These cementing materials may be either silicate minerals or non-silicate minerals, such as calcite.<ref name="boggs-2006-119-135"/>
* Silica cement can consist of either quartz or [[opal]] minerals. Quartz is the most common silicate mineral that acts as cement. In sandstone where there is silica cement present, the quartz grains are attached to cement, which creates a rim around the quartz grain called overgrowth. The overgrowth retains the same crystallographic continuity of quartz framework grain that is being cemented. Opal cement is found in sandstones that are rich in [[volcano]]genic materials, and very rarely is in other sandstones.<ref name="boggs-2006-119-135"/>
* Calcite cement is the most common carbonate cement. Calcite cement is an assortment of smaller calcite crystals. The cement adheres to the framework grains, cementing the framework grains together.<ref name="boggs-2006-119-135"/>
* Other minerals that act as cements include: [[hematite]], [[limonite]], [[feldspar]]s, [[anhydrite]], [[gypsum]], [[barite]], [[clay minerals]], and [[zeolite]] minerals.<ref name="boggs-2006-119-135"/>

Sandstone that becomes depleted of its cement binder through weathering gradually becomes friable and unstable. This process can be somewhat reversed by the application of tetraethyl orthosilicate (Si(OC<sub>2</sub>H<sub>5</sub>)<sub>4</sub>) which will deposit amorphous silicon dioxide between the sand grains.<ref>{{cite journal |last1=Zárraga |first1=Ramón |last2=Alvarez-Gasca |first2=Dolores E. |last3=Cervantes |first3=Jorge |title=Solvent effect on TEOS film formation in the sandstone consolidation process |journal=Silicon Chemistry |date=1 September 2002 |volume=1 |issue=5 |pages=397–402 |doi=10.1023/B:SILC.0000025602.64965.e7|s2cid=93736643 }}</ref> The reaction is as follows.

:Si(OC<sub>2</sub>H<sub>5</sub>)<sub>4</sub> (l) + 2 H<sub>2</sub>O (l) → SiO<sub>2</sub> (s) +  4 C<sub>2</sub>H<sub>5</sub>OH (g)