Changes

* '''Rock grains.''' The grains that make up the bulk of sandstones can be classified into several different categories based on their mineral composition:

* '''Rock grains.''' The grains that make up the bulk of sandstones can be classified into several different categories based on their mineral composition:

*# '''[[Quartz]] grains''': are the most dominate, moderately rounded, subhedral, have high degree of hardness, and are chemical stable which allows them to survive multiple recycling events.

*# '''Quartz grains''': are the most dominate, moderately rounded, subhedral, have high degree of hardness, and are chemical stable which allows them to survive multiple recycling events.

*# '''Feldspars''': commonly alkali feldspars and plagioclase feldspars. Alkali feldspar consists of complete solid solution consisting group of minerals in which the chemical composition of the mineral can range from KAlSi3O8 to NaAlSi3O8 while Plagioclase feldspars are a complex group of solid solution minerals that range in composition from NaAlSi3O8 to CaAl2Si2O8.

*# '''Feldspars''': commonly alkali feldspars and plagioclase feldspars. Alkali feldspar consists of complete solid solution consisting group of minerals in which the chemical composition of the mineral can range from KAlSi3O8 to NaAlSi3O8 while Plagioclase feldspars are a complex group of solid solution minerals that range in composition from NaAlSi3O8 to CaAl2Si2O8.

*# '''Lithic fragments''': are pieces of ancient source rock that have yet to weather away to individual mineral grains. Lithic grains may be any fine-grained or coarse- grained [[igneous]], metamorphic, or sedimentary rock. Although, the most commonly they are clasts of volcanic rocks.

*# '''Lithic fragments''': are pieces of ancient source rock that have yet to weather away to individual mineral grains. Lithic grains may be any fine-grained or coarse- grained [[igneous]], metamorphic, or sedimentary rock. Although, the most commonly they are clasts of volcanic rocks.