PEGMATITE

Pegmatite

A pegmatite is a very crystalline, intrusive igneous rock composed of interlocking crystals usually larger than 2.5 cm in size; such rocks are referred to as pegmatitic.

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pegmatite

Noun

  1. A coarsely crystalline igneous or plutonic rock composed primarily of feldspar and quartz, normally with muscovite and/or biotite mica. Often contains other minerals, which may be of economic importance. Pegmatite is chemically identical to granite, but has a much coarser crystal structure. Common colors are gray, white, and pink. Pegmatite is quarried for decorative stone and as a source of beryllium, columbium and tantalum when these are present. Gemstones of the quartz/silicate family may also be found in pegmatites.


The above text is a snippet from Wiktionary: pegmatite
and as such is available under the Creative Commons Attribution/Share-Alike License.

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