•A naturally occurring granular material composed of finely divided rock and mineral particles. It is defined by its particle size, which ranges in diameter from 0.0625 millimetres to 2 millimetres.
•Made up of individual particles that are within this size range, each of these particles is called a sand grain.
•A simple way to identify sand is its gritty feel when rubbed between the fingers, this is in contrast to silt which feels like flour as it has a smaller particle size.
•The composition of sand is highly variable depending on environmental conditions and local rock sources. This is often the reason for the variety of sand colours (black, red, yellow, white) across the world.
•Sand is predominantly compromised of silica (silicon dioxide, or SiO2), with this silica content deriving largely from quartz grains.
•Quartz is the most common silica crystal and the second most common mineral on the earth's surface. In addition to this, it is found in almost every type of rock; igneous, metamorphic and sedimentary. Due to its chemical inertness and hardness, quartz is the most common mineral that is resistant to weathering. It is these properties that makes quartz a major constituent in sand.
