Palygorskite
Mineral (Mg,Al)2Si4O10(OH)·4H2O
Also called Attapulgite, Mountain leather, and Mountain cork
About it
Tough, felted sheets of fibres that look like leather or cork, light enough to float when dry; named for Palygorsk in the Urals and mined as attapulgite clay in Georgia and Florida.
- Type
- Mineral
- Group
- Silicate (phyllosilicate), palygorskite group
- Formula
- (Mg,Al)2Si4O10(OH)·4H2O
- Hardness (Mohs)
- 2–2.5
- Streak
- white
- Lustre
- earthy, waxy
- Crystal system
- Monoclinic
- Colours
- white, grey, yellowish, grey-green
- Transparency
- opaque
- Cleavage and fracture
- fibrous; tough felted sheets
Typical values: real specimens vary. For more, see mindat.org.