Sand Sand Sand is a granular material composed of finely divided rock and mineral particles. It is defined by size, being finer than gravel and coarser than silt. Sand can also refer to a textural class of soil or soil type; i.e., a soil containing more than 85 percent sand-sized particles by mass. The composition of sand varies, depending on the local rock sources and conditions, but the most common constituent of sand in inland continental settings and non-tropical coastal settings is silica (silicon dioxide, or SiO), usually in the form of quartz. The second most common type of sand is
Eluvium the largest tin mines in the world. Weathering "supergene" enrichment of an apatite rich carbonatite in Ontario has produced a significant eluvial phosphate ore deposit. Eluvium In geology, eluvium or eluvial deposits are those geological deposits and soils that are derived by "in situ" weathering or weathering plus gravitational movement or accumulation. The process of removal of materials from geological or soil horizons is called eluviation or leaching. There is a difference in the usage of this term in geology and soil science. In soil science, eluviation is the transport of soil material from upper layers of soil to lower