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(Al,Mg)2(OH)2(Si,Al)4O10. It is common for Mg or Fe2+ to substitute for Al on the Y site and a corresponding increase in Si on the Z site in the mica group formula X2Y4–6Z8 O20( OH, F)4. 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]
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(Al,Mg)2(OH)2(Si,Al)4O10. It is common for Mg or Fe2+ to substitute for Al on the Y site and a corresponding increase in Si on the Z site in the mica group formula X2Y4–6Z8 O20( OH, F)4. 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]