Gold Hill Standard Mine, Gold Hill, Gold Hill District (Clifton District), Tooele Co., Utah, USA

Al₂Si₂O₅(OH)₄

Crystal System: triclinic
Colour: white to cream and pale-yellow
Habitus: visible crystals are rare. Usually, as micrometer to nanometer-size crystals, having a pseudo-hexagonal platy morphology.
Hardness: 2 - 2½
Fracture: irregular/uneven, conchoidal, sub-conchoidal or micaceous
Cleavage: perfect on {001}
Density: 2.63 g/cm³ 
Origin and geological occurrence: it replaces other aluminosilicate minerals during hydrothermal alteration and weathering. A common constituent of the clay-size fraction of sediments, where it may be formed by direct precipitation. Kaolinite is the main constituent of the kaolin rock. Kaolin is largely used in industry as fillers and coating on papers, in inks,in paints, as absorbant etc.

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Samples:

9E.4 Kaolin White earthy compact mass of clay-like kaolinite. #economic minerals, #phyllosilicates