Class : Silicates
    Subclass : Phyllosilicates
    Crystal system : Monoclinic
    Chemistry : Al₂Si₂O₅(OH)₄
    Rarity : Rare to uncommon

Nacrite is a phyllosilicate, polymorph of dickite and kaolinite, belonging to the kaolinite-serpentine group. Its certain occurrences are rare, but it is probably more abundant than its number of deposits would suggest, its rigorous identification requiring significant analytical resources. Nacrite is formed by alteration of aluminous minerals, notably feldspars, or by hydrothermal deposition in pegmatites and in certain hydrothermal veins. Its name refers to the French nacre (mother-of-pearl) due to its particularly pearly luster. Transparent to translucent in crystals, opaque in mass, nacrite is colorless or white and has perfect cleavage according to {001}. It commonly appears in compact masses with a smooth feel or in lamellar aggregates. Its crystals are rare, forming pseudohexagonal lamellae no more than a centimeter in size, sometimes grouped in sheaves or radiated tufts. Nacrite offers the same wide range of uses as its polymorph kaolinite : ceramics, rubber industry, chemical industry (ion exchange material, saponifiers, degreasers). But the rarity of large deposits leads to fairly marginal industrial use.

Main photo : Nacrite from Trudeau quarry, Quebec, Canada © Stephan Wolfsried

No twin known for this mineral species.

No fakes recorded for this mineral species.