palygorskite

{{Infobox mineral | name = Palygorskite | boxwidth = | boxbgcolor =#b7a98f | image = Mineraly.sk - palygorskit.jpg | imagesize = 260px | alt = | caption = A sample of palygorskite from Hnúšťa, Slovakia. | category = Phyllosilicate minerals | group = Palygorskite group | formula = Al2Mg2◻2Si8O20(OH)2(H2O)4 · 4H2O | IMAsymbol = Plg | molweight = | strunz = 9.EE.20 | system = Monoclinic, orthorhombic | class = Prismatic (2/m) (same H-M symbol) | symmetry = B2/m and setting C2/m, P 21 21 21 | unit cell = a = 12.78 Å, b = 17.86 Å, c = 5.24 Å; β = 95.78°; Z = 4 | color = White, grayish, yellowish, gray-green | colour = | habit = Commonly fibrous (asbestiform), tangled mats known as mountain leather. Individual, small crystals are lath-shaped | twinning = | cleavage = Distinct/good, good on {110} | fracture = | tenacity = Tough | mohs = 2 – 2.5 | luster = Waxy, earthy | streak = | diaphaneity = Translucent | gravity = 1 – 2.6 | density = 2.1 - 2.6 g/cm3 (Measured); 2.35 g/cm3 (Calculated) | polish = | opticalprop = Biaxial (−) | refractive = nα = 1.522 – 1.528 nβ = 1.530 – 1.546 nγ = 1.533 – 1.548 | birefringence = δ = 0.011 – 0.020 | pleochroism = X= pale yellow Y=Z= pale yellow-green | 2V = | dispersion = | extinction = | length fast/slow = | fluorescence = | absorption = | melt = | fusibility = | diagnostic = | solubility = | impurities =Fe,K | alteration = | other = | prop1 = | prop1text = | references = }}

Palygorskite or attapulgite is a magnesium aluminium phyllosilicate with the chemical formula ) that occurs in a type of clay soil common to the Southeastern United States. It is one of the types of fuller's earth. Some smaller deposits of this mineral can be found in Mexico, where its use is tied to the manufacture of Maya blue in pre-Columbian times.