SANDSTONE

Colour: Very variable; frequently red, brown, greenish, yellow, grey, white.

Texture: Medium-grained. Usually well sorted, that is grains all about the same size; grains sub angular to rounded (sandstone).

Structure: Bedding usually apparent; current bedding and ripple marks common; graded bedding may occur. Concretions and fossils may be found.

Mineralogy: Quartz is the main component but is often accompanied by feldspar, mica or other minerals. The grains may be cemented by silica, calcite or iron oxides.

Field relations: Sandstones are associated with most other sedimentary rocks. Most sands accumulated either in water, usually the sea, or as wind-blown deposits in arid continental areas. Desert sandstones tend to be red, and the individual sand grains are often almost spherical and polished." (Hamilton et al 1976, 194)

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