Sharp sand

Further information: Grus (geology)

Sharp sand, also known as grit sand or river sand and as builders' sand, concrete sand, or ASTM C33 when medium or coarse grain, is a gritty sand used in concrete and potting soil mixes or to loosen clay soil^[1] as well as for building projects. It is not cleaned or smoothed to the extent recreational play sand is. It is useful for drainage.^[2] It is an angular grained sand.^[3] It was used in the production of brass.^[4] It is now used in the building trade. Sand and gravel ridges known as eskers are a frequently used source.^[5]