Clay between silts and clays based on the plasticity properties of the soil, as measured by the soils' Atterberg limits. ISO 14688 grades clay particles as being smaller than 2 μm and silt particles as being larger. Mixtures of sand, silt and less than 40% clay are called loam. Loam makes good soil and is used as a building material. Clay minerals typically form over long periods of time as a result of the gradual chemical weathering of rocks, usually silicate-bearing, by low concentrations of carbonic acid and other diluted solvents. These solvents, usually acidic, migrate through the weathering rock after
Quartz arenite is known as a multicycle sand. Quartz arenite A quartz arenite or quartzarenite is a sandstone composed of greater than 90% detrital quartz, with limited amounts of other framework grains (feldspar, lithic fragments, etc.) and matrix. It can have higher-than-average amounts of resistant grains, like chert and minerals in the ZTR index. The term 'quartz arenite' is derived from the main component (quartz) and arenite, a Latin term for a rock with sand-sized grains. In some literature, these can be called orthoquartzites, a confusing term which usually refers to the metamorphic rock quartzite, though most metamorphic quartzites are diagentically fused