What type of rock is pyrophyllite?
pyrophyllite, very soft, pale-coloured silicate mineral, hydrated aluminum silicate, Al2(OH)2 Si4O10, that is the main constituent of some schistose rocks. The most extensive commercial deposits are in North Carolina, but pyrophyllite is also mined in California, China, India, Thailand, Japan, Korea, and South Africa.
Is pyrophyllite metamorphic?
Pyrophyllite is an early stage metamorphic mineral and is actually quite common although usually not very abundant as good mineral specimens. It is found as a constituent of slate, phyllite (which is not named after pyrophyllite), some schists and other early stage metamorphic rocks.
What is pyrophyllite talc?
Pyrophyllite is a hydrous aluminum silicate with a structure similar to talc. Such properties as chemical inertness, high dielectric strength, high melting point, and low electrical conductivity make it useful for ceramic and refractory applications.
What is the use of pyrophyllite?
Due to its chemical and physical properties, pyrophyllite is very suitable as a filler and is thus used in the paper, plastic, paint, insecticide, and pharmaceutical industries. Papermakers seek to reduce costs and increase product quality through the use of fillers.
How is pyrophyllite formed?
The mineral paragenesis in the pyrophyllite deposits suggests that the formation of minerals took place in two ways: (1) the transformation of kyanite into pyrophyllite and quartz through retrograde metamorphism by a high degree temperature, (2) then pyrophyllite and probably muscovite were transformed into kaolinite …
What is pyrophyllite clay?
Pyrophyllite is a phyllosilicate mineral composed of aluminium silicate hydroxide: Al2Si4O10(OH)2. It occurs in two forms (habits): crystalline folia and compact masses; distinct crystals are not known. Pyrophyllite.
What does pyrophyllite look like?
This variety, when heated , exfoliates and swells up to many times its original volume, hence the name pyrophyllite, from the Greek pyros (fire) [clarify] and phyllos (a leaf), given by R. Hermann in 1829. The color of both varieties is white, pale green, greyish or yellowish; they are very soft ( hardness of 1.0 to 1.5)…
What is pyrophyllite used for in clay?
Pyrophyllite is easily machineable and has excellent thermal stability, so it is added to clay to reduce thermal expansion when firing, but it has many other industry uses when combined with other compounds, such as in insecticide and for making bricks.
Where is pyrophyllite found in Australia?
Localities where good Pyrophyllite specimens have come from are limited. Radiating yellow sprays come from Gundagai, New South Wales, Australia; and Monte Folgorito, Pietrasanta, Tuscany, Italy. Light green Pyrophyllite was found in St Niklaus, Zermatt-Saas Fee area, Valais, Switzerland.
Is pyrophyllite similar to talc?
It is very similar to Talc, with very similar properties and habits. However, it has distinct radiating crystal aggregates which easily identify it. Pyrophyllite is named after the Greek words ” pyr ” – “fire” and ” phyllon ” – leaf, regarding its property to exfoliate into fan shapes upon heating.
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