Sediments are transformed into sedimentary rock through cementation.
This is a process that precipitates minerals in the spaces between
sediment particles. As sediments are deposited, water moves through the
pores between the grains. The water commonly contains dissolved silica
(SiO2) or calcium carbonate (CaCO3). If the
chemical conditions are right, quartz or calcite crystals will
precipitate in the spaces between the sand grains. They will grow until
the spaces are filled up and interlocking. The crystals cement
the sediment together, creating solid rock.
Cemented gravel and pebbles form a sedimentary rock called
conglomerate. Artificial cemented rocks (sand and gravel) is called concrete.
Cemented sand forms sandstone and mud-sized particles make mudstone and
siltstone. The type of cement also helps classify the sedimentary rock.
Grains become cemented together