Paragonite

Paragonite, also known as Natron-Glimmer, is a mineral, related to muscovite. Its empirical formula is NaAl₂(Si₃Al)O₁₀(OH)₂. A wide solvus separates muscovite from paragonite, such that there is little solid solution along the vector Na⁺K⁺ and apparent micas of intermediate composition is most commonly a microscopic (or even sub-microscopic) intergrowth of two distinct micas, one rich in K, and the other in Na. Paragonite is a common mineral in rocks metamorphosed under blueschist facies conditions along with other sodic minerals such as albite, jadeite and glaucophane. During the transition from blueschist to greenschist facies, paragonite and glaucophane are transformed into chlorite and albite.[4]

It was first described in 1843 for an occurrence at Mt. Campione, Tessin, Switzerland.[2] The name derives from the Greek, paragon, for misleading, due to its similar appearance to talc.[3]

References

1. ^ Mindat
2. ^ a b Webmineral
3. ^ a b Handbook of Mineralgy
4. ^ Deer, W. A., et.al., Rock-forming minerals, Volume 3A Micas, Geological Society of London, 2nd ed. 2006, p. 302 ISBN 978-1862391420

List of minerals