Dickite - Encyclopedia

    Class : Silicates
    Subclass : Phyllosilicates
    Crystal system : Monoclinic
    Chemistry : Al₂Si₂O₅(OH)₄
    Rarity : Quite common

Dickite is a phyllosilicate, polymorph of nacrite and kaolinite, belonging to the kaolinite-serpentine group. Its certain occurrences are quite frequent, but dickite is probably much more abundant than its number of deposits suggests, its rigorous identification requiring significant analytical resources. It is a mineral mainly of hydrothermal origin, which forms by alteration at low temperature of aluminous minerals, in particular feldspars, around hydrothermal veins and within them. It was named in honor of the chemist and metallurgist Allan Brugh Dick. Dickite is transparent to translucent in crystals, opaque in mass. It appears in lamellar aggregates or in compact white masses, sometimes yellowish-green, with a smooth feel, made up of microscopic crystals. The visible crystals are rare, forming pseudohexagonal lamellae of 4 mm at most, sometimes grouped in sheaves or radiated aggregates. It offers the same wide range of uses as kaolinite : ceramics, papermaking, rubber industry, ion exchange material, saponifiers, degreasers, but the rarity of large deposits results in fairly marginal use.

Main photo : Dickite from Mas Lavayre, Lodève, Hérault, France © Oliver Dziallas

No twin known for this mineral species.

No fakes listed for this mineral species.