Sand is a type of sediment derived from the weathering of rocks such as granite. The feldspar in granite weathers to clay, and the quartz grains in granite are released as sand particles. Silt forms form the weathering of rocks. Clay is both a size term and a mineral term. Clay is produced when certain minerals, such as feldspar, are weathered in the presence of water.
Soils contain particles of different sizes.
The texture of a soil influences its ability to transmit and retain water and air, both of which are essential to growth. Sandy soils drain quickly. Clay-rich soils inhibit drainage, and plant roots may have difficulty penetrating clay. A loam is a soil in which there is a mixture of sand and silt, with a small amount of clay. Loam soils are best suited to support plant life.