All Minerals

Pyrophyllite

Formula: AlSi2O5OH

Pyrophyllite is an aluminum silicate mineral with a similar chemical structure to talc (a magnesium silicate). It is non-plastic yet clay-like and often used in ceramic bodies to decrease thermal expansion and moisture expansion during service. It is a very soft white mineral (also resembling talc in physical appearance and feel).

Three types are found in nature:
-Micaceous foliated pyrophyllite (flaky with some fluxes).
-Crystalline (higher expansion and longer needle-like grains).
-Homogeneous variety known as massive pyrophyllite. It is used in refractories because it lacks fluxes and has a rounded grain with high lubricity that lends itself to pressing bodies. This type typically has a permanent expansion of about 2% to 2000F.

Phyrophyllite can be variable in nature, so factory blending and select mining are normal. Many other minerals can be found associated with it (e.g. kyanite, andalusite, topaz, quartz, sericite, chlorotoid, pyrite, chlorite, feldspar, hematite, magnetite).

Some grades of Phyrophyllite can be variable in nature, so factory blending and select mining are normal. Many other minerals can be found associated with it (e.g. kyanite, andalusite, topaz, quartz, sericite, chlorotoid, pyrite, chlorite, feldspar, hematite, magnetite).

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