Class : Silicates
    Subclass : Phyllosilicates
    Crystal system : Monoclinic
    Chemistry : Al₂Si₄O₁₀(OH)₂
    Rarity : Common

Pyrophyllite is a phyllosilicate resulting from the hydrothermal alteration of aluminous rocks. Its genesis requires acidic conditions and a temperature above 400°C. This mineral is similar to talc in its structure, appearance and physical properties, notably its very low hardness. It is a sometimes essential mineral in certain aluminous metamorphic rocks. Its name comes from the Greek pûr (fire) and phullon (leaf), because this mineral exhibits exfoliation when strongly heated. Pyrophyllite occurs in crystals, often clear, forming hexagonal lamellar plates united in flattened rosettes, grayish white to greenish white-yellow, sometimes gray-green in color. Pyrophyllite is widely exploited for its applications in the mineral filler industry, particularly in stationery, paints, the rubber and cosmetics industries, it is also a thermal and electrical insulator. The agalmatolite variety, sometimes also called pagodite, is exploited in China and widely worked for the production of statuettes and art objects.

Main photo : Pyrophyllite from Indian Gulch Mine, California, USA © Rob Lavinsky

No twins known for this mineral species.

No fakes listed for this mineral species.