Pegmatite
A pegmatite is an igneous rock with a very rough texture, which has large interlocking crystals[1] that are usually bigger than 1 centimeter (0.4 in) and sometimes bigger than 1 meter (3 ft).[2]
Many of the world's largest crystals are found in pegmatites. These include crystals of quartz, mica, beryl, and tourmaline. Some of these crystals are over 10 m (33 ft) long.[3]
Etymology
The word pegmatite comes from the Homeric Greek word, πήγνυμι (pēgnymi), which means “to bind together." This refers to the interlocked crystals in the rock's texture.[4]
Pegmatite Media
Pegmatite containing lepidolite, tourmaline, and quartz from the White Elephant Mine in the Black Hills, South Dakota
Proterozoic pegmatite swarm in the headwall of the cirque of a small mountain glacier, northeastern Baffin Island, Nunavut
Rose muscovite from the Harding pegmatite mine
Blue apatite crystals at the Harding pegmatite mine
Pegmatitic granite with pink potassium feldspar crystals, surrounding a finer-grained cumulate-filled enclave, Rock Creek Canyon, eastern Sierra Nevada, California
Elbaite tourmaline (olive-green) and lepidolite mica (violet), from a lithium-enriched pegmatite in Brazil
Scatter plots of lithium grade and tonnage for selected world deposits, as of 2017
Pegmatite (light colored) in dark mica schist, Île de Noirmoutier, France
Pegmatite (pink), Isle of Skye, Scotland
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References
- ↑ Glossary of Geology. (1997). Alexandria, Viriginia: American Geological Institute. ISBN 0922152349.
- ↑ Blatt, Harvey. Petrology: Igneous, Sedimentary, and Metamorphic. (1996). New York: W.H. Freeman. p. 73. ISBN 0716724383.
- ↑ Schwartz, G.. The Black Hills Mineral Region. American Mineralogist 13 (1928). p. 56–63.
- ↑ London, David. The Pegmatite Puzzle (in en). Elements 8 (4) (2012-08-01). p. 263–68. doi:10.2113/gselements.8.4.263.
