Pegmatite with blue corundum crystalsPegmatite containing lepidolite, tourmaline, and quartz from the White Elephant Mine in the Black Hills, South DakotaProterozoic pegmatite swarm in the headwall of the cirque of a small mountain glacier, northeastern Baffin Island, Nunavut
A pegmatite is an igneous rock showing a very coarse texture, with large interlocking crystals usually greater in size than 1 cm (0.4 in) and sometimes greater than 1 meter (3 ft). Most pegmatites are composed of quartz, feldspar, and mica, having a similar silicic composition to granite. However, rarer intermediate composition and mafic pegmatites are known.
Many of the world's largest crystals are found within pegmatites. These include crystals of microcline, quartz, mica, spodumene, beryl, and tourmaline. Some individual crystals are over 10 m (33 ft) long.[1]
Most pegmatites are thought to form from the last fluid fraction of a large crystallizing magma body. This residual fluid is highly enriched in volatiles and trace elements, and its very low viscosity allows components to migrate rapidly to join an existing crystal rather than coming together to form new crystals. This allows a few very large crystals to form. While most pegmatites have a simple composition of minerals common in ordinary igneous rock, a few pegmatites have a complex composition, with numerous unusual minerals of rare elements. These complex pegmatites are mined for lithium, beryllium, boron, fluorine, tin, tantalum, niobium, rare earth elements, uranium, and other valuable commodities.
^Schwartz, G. (1928). "The Black Hills Mineral Region". American Mineralogist. 13: 56–63.
A pegmatite is an igneous rock showing a very coarse texture, with large interlocking crystals usually greater in size than 1 cm (0.4 in) and sometimes...
The Tin Mountain pegmatite is an igneous intrusion located in the southern Black Hills, South Dakota. It is a part of the Harney Peak Granite dome that...
Pampean Pegmatite Province (Spanish: Provincia Pegmatítica Pampeana) is a geological area in central and northwestern Argentina rich in pegmatites. The province...
the eastern edge by the Blue Ridge Front. The pegmatites intruded into the Ashe Formation. The pegmatites and country rock are part of the Spruce Pine...
exhibits—all designed to inspire visitors about Maine's geologic history, pegmatite mining, and our planet's place in the solar system. The museum was formed...
The Harding Pegmatite Mine is a former adit mine that extracted lithium, tantalum, and beryllium from a Precambrian pegmatite sill. It ceased operations...
visited the point and gave the name because of the abundance of the rock Pegmatite. 84°56′S 166°56′W / 84.933°S 166.933°W / -84.933; -166.933. A Y-shaped...
granites, pegmatites, and schists, and "books" (large individual crystals) of mica several feet across have been found in some pegmatites. Micas are...
the Ross Ice Shelf. From the south, features include Patterson Peak, Pegmatite Peak, Feeney Peak, Feeney Col and Hidden Col. Along the Ross Ice Shelf...
noted in beryl dissolution cavities at the Noumas II Pegmatite, part of the Orange River pegmatite belt in the Northern Cape of South Africa. Large crystals...
Western Cape Sweden: Skuleboda mine, Västra Götaland County: found in pegmatite United States: Colorado: Deer Trail, Arapahoe County:233 Custer County:234...
minerals; this is called a pegmatite. The high water content of the magma made it possible for the crystals to grow quickly, so pegmatite crystals are often quite...
Lepidolite is found with other lithium-bearing minerals, such as spodumene, in pegmatite bodies. It has also been found in high-temperature quartz veins, greisens...
commonly found in phosphate-rich pegmatites. It occurs in the form of perfect crystals grouped in druses, in pegmatites, and is often of precious-stone...
margins of granitic intrusions. In some locations, very coarse-grained pegmatite masses occur with granite. Granite forms from silica-rich (felsic) magmas...
In southern Greenland, the Illimaussaq alkaline complex consists of pegmatites such as nepheline, syenites (especially kakortokite or naujaite) and sodalite...
photosensitive and subject to fading. The first crystals were found in a pegmatite found near Rumford, Maine, US, and in Minas Gerais, Brazil. The crystals...
spodumene hard-rock. The two largest pegmatites (known as the Carriere de l'Este Pegmatite and the Roche Dure Pegmatite) are each of similar size or larger...
of these are concentrated in exceptionally coarse-grained rocks called pegmatites that are typically found in dikes and veins near larger igneous masses...
aluminium, phosphate, fluoride and hydroxide. The mineral occurs in pegmatite deposits and is easily mistaken for albite and other feldspars. Its density...
partial melting: either process can form the magma that crystallizes to pegmatite, a rock type commonly enriched in incompatible elements. Bowen's reaction...
refined for use in industry. Spodumene occurs in lithium-rich granite pegmatites and aplites. Associated minerals include: quartz, albite, petalite, eucryptite...
mesosome), and another of which has the appearance of an intrusive rock such pegmatite, aplite, or granite the (leucosome). The rock may also contain a melanosome...
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