What is sand made of? and why does the colour of the sand vary in different areas?

Answer 1

Sand is a granular material made up of fine rock particles. Sand is a naturally occurring, finely divided rock, comprising particles or granules ranging in size from 0.0625 (or 1⁄16 mm) to 2 millimeters. An individual particle in this range size is termed a sand grain. The next smaller size class in geology is silt: particles below 0.0625 mm down to 0.004 mm in size. The next larger size class above sand is gravel, with particles ranging from 2 mm up to 64 mm (see particle size for standards in use). Sand feels gritty when rubbed between the fingers (silt feels like flour). Sand is commonly divided into five sub-categories based on size: very fine sand (1/16 - 1/8 mm), fine sand (1/8 mm - 1/4 mm), medium sand (1/4 mm - 1/2 mm), coarse sand (1/2 mm - 1 mm), and very coarse sand (1 mm - 2 mm). These sizes are based on the Φ sediment size scale, where size in Φ = -log base 2 of size in mm. On this scale sand is from Φ = -1 to 4, with the divisions between sub-categories at whole numbers.

The most common constituent of sand, in inland continental settings and non-tropical coastal settings, is silica (silicon dioxide, or SiO2), usually in the form of quartz, which, because of its chemical inertness and considerable hardness, is resistant to weathering. The composition of sand varies according to local rock sources and conditions. The bright white sands found in tropical and subtropical coastal settings are ground-up limestone. Arkose is a sand or sandstone with considerable feldspar content which is derived from the weathering and erosion of a (usually nearby) granite. Some locations have sands that contain magnetite, chlorite, glauconite or gypsum. Sands rich in magnetite are dark to black in color, as are sands derived from volcanic basalts. The chlorite-glauconite bearing sands are typically green in color, as are sands derived from basalts (lavas) with a high olivine content. The gypsum sand dunes of the White Sands National Monument in New Mexico are famous for their bright, white color. Sand deposits in some areas contain garnets and other resistant minerals, including some small gemstones (:

Answer 2

Sand is Silica or Silicon Dioxide which is white in color.
The color varies because of the presence of the other inorganic compounds as impurities
Consult any Geology Text in your library.
You will see the pictures of the strata of the earth's surface.

Answer 3

Sand is just rock that has been ground up very fine. It's different colors depending upon the type of rock it came from.

Answer 4

finely ground up stone