Palygorskite

montmorillonite

talc

Formula: (Mg,Al)2Si4O10(OH).4H2O
Phyllosilicate (sheet silicate)
Specific gravity: 1 to 2.6
Hardness: 2 to 2½
Streak: White
Colour: White, greyish, yellowish, grey-green
Solubility: Insoluble in acids, infusible (Dana)
Environments

Igneous environments
Pegmatites
Sedimentary environments
Hydrothermal environments

Palygorskite occurs in hydrothermal veins, in basalt, in syenite and granite, in granite pegmatites and in sediments. It occurs in deep sea sediments, in continental slope or margin deposits, and in lacustrine marl. It develops in soils of arid and semi-arid regions (Dana, HOM). Although palygorskite can form quite large crystals it more commonly occurs as leathery-looking masses. Common associates include calcite, dolomite, talc, chlorite, quartz, chalcedony and opal, and montmorillonite (HOM).

At the Trimouns quarry, Luzenac, Ariège, Occitanie, France, palygorskite is found in dolomite joints as millimetre-sized fibres arising from alteration of phyllosilicates; it may be associated with allanite or bastnäsite (Minrec 35.3.240).

At the Monte Rosa mine, Ica department, Peru, opal veins sometimes contain felt-like aggregates of white palygorskite (Minrec 42.2.168).

The type locality is the Second Mine, Popovka River, Permskaya Oblast, Russia.

in the Springbok Flats, Okiep Copper District, Namakwa District, Northern Cape, South Africa, palygorskite is presently forming from montmorillonite (AM 54.198-205).

At the Bradgate quarries, Groby, Leicestershire, England, UK, palygorskite has been found associated with dolomite and malachite, and separately associated with pseudomorphs after halite. It has also been found in joints in diorite (JRS 14.58). At Mwyndy Mine, Llantrisant, South Wales, UK, palygorskite has been found with hematite (MW).

At TÅ·Coch, near Porthcawl, South Wales, UK, palygorskite has been found coating shear surfaces in manganese ore (MW).

At Attapulgus, Decatur county, Georgia, USA, palygorskite has been found containing abundant finely-divided quartz and minor montmorillonite (AM 54.198-205).

At the Bates Meerschaum Mine, near Sapillo Creek, Grant County, New Mexico, USA, palygorskite occurs in hydrothermal calcite veins in a volcanic conglomerate (AM 54.198-205).

At the Shady Formation, Lone Jack Quarry, Rockbridge County, Virginia, USA, palygorskite has been found containing finely-divided calcite (AM 54.198-205).

Near Metaline Falls, Stevens county, Washington, USA, palygorskite has been found containing abundant finely-divided quartz and pyrite (AM 54.198-205).

Common impurities: Fe,K

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