Phengite

Phengite

Phengite
General
Category Mica group
Formula
(repeating unit)
K(AlMg)2(OH)2(SiAl)4O10

Phengite is a series name for dioctahedral micas of composition K(AlMg)2(OH)2(SiAl)4O10, similar to muscovite but with addition of magnesium. It is a non-IMA recognized mineral name representing the series between muscovite and celadonite.[1][2]

The silica content of phengite has been proposed as a geobarometer for the metamorphism of low grade schists.[3]

References

  1. Mindat.org
  2. Mineralienatlas: Phengit
  3. M. E. Fleet and R. A. Howie, Rock-Forming Minerals, Vol. 3A: Micas, Geological Society of London; 2nd ed, 2006, p. 132, ISBN 1-86239-142-4 (accessed through Google books)
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