Mineral Information and Data:

Aliettite
Ca0.2Mg6(Si,Al)8O20(OH)4 • 4H2O [CNMNC approved formula]

Named in 1969 for Professor Andrea Alietti (1923-), clay mineralogist of the University of Modena, Modena, Italy, who first studied the structure of the mineral.

IMA status : Redefined IMA Approved; 1981 ()
CLASSIFICATION 
Dana
(8th edition) :
71.04.02.08  
  (71) Phyllosilicate Sheets of Six-Membered Rings
  (71.04) interlayered 1:1, 2:1, and octahedra
  (71.04.02) Interstratified Chlorite-Smectite group
  
Nickel-Strunz
(10th edition) :
09.EC.60
  (09) Silicates
  (09.E) Phyllosilicates
  (09.EC) Phyllosilicates with mica sheets, composed of tetrahedral and octahedral nets
  
Crystal system: Monoclinic System
Point group (H-M): Unknown — Unk
Unit cell: a = 5.216 Ǻ, b = 24.6 Ǻ
Crystal Habit: Irregular, tabular to platy crystals, < 2 ¹m, with curled edges when viewed under the electron microscope; as microscopic rounded aggregates.
  
Color: White, Dark green, Buff
Diaphaneity: Translucent
Luster: Dull
Hardness (Mohs): 1-2
Streak: White
  
Geologic Setting: An alteration product in serpentinized ophiolites and residual in soils derived therefrom; in altered dolostones.
Mineral Association: Talc, chlorite, serpentine, calcite
  
Comments: Positive identification of this mineral may need data from DTA curves, dehydration curves, and X-ray powder patterns before and after treatment by heating and with organic liquids.

 

Aliettite
Tan to brownish pseudomorph of aliettite after wollastonite.
Origin: Ingichka, Uzbekistan.
Photo: Jeff Weissman

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