Nacrite

Nacrite
Nacrite, "Frohe Hoffnung"-shaft, Wildental, Erzgebirge
General
Category	Phyllosilicates Kaolinite-serpentine group
Formula (repeating unit)	Al₂Si₂O₅(OH)₄
Strunz classification	9.ED.05
Crystal system	Monoclinic Domatic class
Space group	Monoclinic H-M symbol: (m) Space group: Cc

Nacrite Al₂Si₂O₅(OH)₄ is a clay mineral that is polymorphous (or polytypic) with kaolinite. It crystallizes in the monoclinic system. X-ray diffraction analysis is required for positive identification.

Nacrite was first described in 1807 for an occurrence in Saxony, Germany. The name is from nacre in reference to the mother of pearl luster of nacrite masses.

References

Phyllosilicates

Serpentine group	Antigorite Chrysotile Lizardite Népouite

Clay mineral group	Allophane Chlorite¹ Dickite Halloysite Illite Kaolinite Montmorillonite Nacrite Nontronite Palygorskite Saponite Sepiolite Serpentine¹ Talc

Mica group	Biotite Glauconite Lepidolite Margarite Muscovite Phlogopite

Chlorite group	Chlorite

1. Serpentine and chlorite are sometimes considered clay minerals

Clay minerals

Allophane Chlorite Dickite Halloysite Hectorite Illite Imogolite Kaolinite Montmorillonite Nacrite Nontronite Palygorskite Saponite Sepiolite Talc

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