phengite


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phengite

(ˈfɛnˌdʒaɪt)
n
1. (Geological Science) a type of transparent selenite
2. (Geological Science) a type of mica or muscovite
References in periodicals archive ?
Flakes of white mica were on the line between muscovite and phengite. Chlorite flakes generally contained traces of titanium and potassium, strongly suggesting that chlorite derived from biotite alteration.
The blueschist facies comprise of sodic amphibole + garnet + phengite + lawsonite and/or epidote [+ or -] omphacite [+ or -] quartz characterizing a broad range of pressure-temperature conditions (12-16 kbar, 380-500 [degrees]C) (Okay, 2002).
The tectonic significance of pre-Scandian [sup.40]Ar/[sup.39]Ar phengite cooling ages in the Caledonides of western Norway.
Analyses of the multiequilibrium between chlorite and phengite solide solution following Lanari et al (2010) method, allow the estimation of metamorphic conditions at 400degC for 5 Kbar for this last event.
In addition, and whilst not a definitive metallurgical study, Dr Halley's work indicated that gold is depleted in the upper oxide area and enriched in the lower oxide to fresh rock transition, and the strongest mineralised zones are also depleted in calcium in phengitic altered zones (phengite is a greenish potassium magnesium mica mineral).
These cavities are partially filled with chlorite, Mg-celadonite, illite, phengite micas or quartz.
There is a high percentage of calcite clasts, which were cemented with a phengite matrix.