Sedimentary rock
Arkose
An arenite with over 10% feldspar, and more feldspar than rock fragments.
In thin section
Look for feldspar grains (twinned plagioclase or microcline, often cloudy) among the quartz.
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More photos and thin sections
Other sedimentary rocks
Conglomerate and breccia · Quartz arenite · Lithic arenite · Wacke (greywacke) · Mudrocks: shale, mudstone, siltstone, claystone · Limestone · Chalk · Coquina · Oolite · Travertine and tufa · Dolostone · Chert · Diatomite · Radiolarite · Evaporites: rock salt and gypsum · Banded iron formation · Coal: peat to anthracite · Oil shale