Sand

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Sand is a granular material composed of finely divided rock and mineral particles. It is defined by size.

All sands contain small quantities of heavy rock-forming minerals, including garnet, tourmaline, zircon, rutile, topaz, pyroxenes, and amphiboles.

In some shore and river sands these heavier constituents, as well as some of the heavy native elements, become concentrated as a result of sorting by currents and the removal of the lighter constituents. Such placer sands may be economically valuable deposits worked for diamonds and other gemstones, gold, platinum, tin, monazite, and other ores.