PALYGORSKITE
Palygorskite is one of the clay minerals - it's a hydrous magnesium aluminosilicate
((Mg,Al)2Si4O10(OH)·4H2O). It
has a nonmetallic luster, is variably colored, has a white streak, is fairly
soft (H = around 2), has flattish & flexible crystals, has one good
cleavage, and can occur as flattish crystals, as earthy masses, or in a finely
fibrous form. Palygorskite is known to occur in a "mountain
leather" variety (see below) that resembles leather.
Palygorskite - "mountain leather" variety from unrecorded locality (Wayne
State University collection, Detroit, Michigan, USA).
Palygorskite - "mountain paper" variety from unrecorded locality (Wayne
State University collection, Detroit, Michigan, USA).