File:Alkaline_pegmatite.jpg · Wikimedia Commons · See Wikimedia Commons
pegmatite
Sign in to savethumb|Pegmatite with blue corundum crystals thumb|Pegmatite containing lepidolite, [[tourmaline, and quartz from the White Elephant Mine in the Black Hills, South Dakota]] thumb|upright=1.25|Proterozoic pegmatite swarm in the headwall of the [[cirque of a small mountain glacier, northeastern Baffin Island, Nunavut]]
~17 min read
Encyclopedic overview
12 sectionsContents
- Etymology
- General description
- Classification
- Petrology
- Mineralogy
- Geochemistry
- Economic importance
- Occurrence
- See also
- References
- Further reading
- External links
thumb|Pegmatite with blue corundum crystals thumb|Pegmatite containing lepidolite, [[tourmaline, and quartz from the White Elephant Mine in the Black Hills, South Dakota]] thumb|upright=1.25|Proterozoic 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 and sometimes greater than . 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.
Excerpted from Wikipedia’s “pegmatite” article, available under the CC BY-SA 4.0 licence.