Dickite, Calcite Dimensions: 4.2 cm × 3.2 cm × 2.2 cm Locality: Lowville quartz locality, Lowville, Lewis County, New York, USA Description: Rare white dickite — Photo: Chris Emproto · CC BY 3.0
Dickite
A kaolinite-family clay mineral named for metallurgical chemist Allan Dick — same chemistry, different layer stacking.
Intro adapted from Wikipedia (CC BY-SA).
Dickite is an IMA-recognized mineral species in the silicate class, with the chemical formula Al₂Si₂O₅(OH)₄.
It crystallizes in the monoclinic crystal system (space group Cc). It is a member of the Clay, Kaolinite structural group.
Key properties: Mohs hardness 2–2.5; specific gravity 2.6; typically white or colorless; white streak; Satiny luster; refractive index 1.565; optically biaxial.
IMA symbol Dck, grandfathered status — known before the IMA’s founding, named in 1930.
Commonly of hydrothermal origin along veins derived in part from the alteration of aluminosilicate minerals. It is also found as an authigenic sedimentary mineral.
It is found associated with Quartz, \chalcedony.".
The name refers to Allan Brugh Dick (1833–1926), Scottish metallurgical chemist, who first described the species.
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