Black sand

Black sand

Black sand is a heavy, glossy, partly magnetic mixture of usually fine sands, found as part of a placer deposit.

Black sands are used by miners and prospectors to indicate the presence of a placer formation. Placer mining activities produce a concentrate that is composed mostly of black sand. Black sand concentrates often contain additional valuables, other than precious metals: rare earth elements, thorium, titanium, tungsten, zirconium and others are often fractionated during igneous processes into a common mineral-suite that becomes black sands after weathering and erosion.

Several gemstones, such as garnet, topaz, ruby, sapphire, and diamond are found in placers and in the course of placer mining, and sands of these gems are found in black sands and concentrates. Purple or ruby-colored garnet sand often forms a showy surface dressing on ocean beach placers.

ee also

* Diamond
* Mining
* Placer deposit
* Heavy mineral sands ore deposits
* Punaluu Black Sand Beach

External links

* [ The Geology of Black Sand]
* [ Black Sands of the Nile River]
* [ Black Sand in Vieques, Puerto Rico]
* [ Alaska Mineral and Mining Images]

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Look at other dictionaries:

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  • black sand — adjective Usage: usually capitalized B&S Etymology: so called from the glacial sand of the Illinois river flood plain near Liverpool, Ill., where remains were found : of or relating to a component of Woodland culture and a physical type first… …   Useful english dictionary

  • black sand — Accumulation of fragments of durable, usually dark, heavy minerals (those with a density greater than that of quartz). These accumulations are found in streambeds or on beaches where stream flow and wave energy are sufficient to carry away low… …   Universalium

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  • Punaluu Black Sand Beach — Saltar a navegación, búsqueda Punaluʻu Black Sand Beach es una playa cercana a Nāʻālehu en la Isla de Hawái, Hawaii. La playa es de arena oscura debido a los escurriemientos de lava volcánica. Geografía La playa de Punaluʻu Black Sand Beach se… …   Wikipedia Español

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  • Sand — /sand/; Fr. /sahonnd/, n. George /jawrj/; Fr. /zhawrddzh/ (Lucile Aurore Dupin Dudevant), 1804 76, French novelist. * * * I Mineral, rock, or soil particles that are 0. 0008–0.08 in. (0.02–2 mm) in diameter. Most rock forming minerals are found… …   Universalium

  • sand — sandable, adj. sandless, adj. sandlike, adj. /sand/, n. 1. the more or less fine debris of rocks, consisting of small, loose grains, often of quartz. 2. Usually, sands. a tract or region composed principally of sand. 3. the sand or a grain of… …   Universalium

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