Mineral Information and Data:

Antigorite
Mg3Si2O5(OH)4 [CNMNC approved formula]

Named in 1840 for the type locality, Valle di Antigorio, Domodossola, Piedmont, Italy.

IMA status : Renamed IMA Approved; 1967 ()
CLASSIFICATION 
Dana
(8th edition) :
71.01.02a.01  
  (71) Phyllosilicate Sheets of Six-Membered Rings
  (71.01) with 1:1 layers
  (71.01.02a) Serpentine group
  
Nickel-Strunz
(10th edition) :
09.ED.15
  (09) Silicates
  (09.E) Phyllosilicates
  (09.ED) Phyllosilicates with kaolinite layers composed of tetrahedral and octahedral nets
  
Crystal system: Monoclinic System
Point group (H-M): m — domatic
Unit cell: a = 43.53 Å, b = 9.259 Å, c = 7.263 Å, b = 91.633°
Crystal Habit: Minute crystals flaky or lath-like; usually massive, very fine-grained; lamellar, columnar, commonly fibrous
Twinning: May exhibit 2- or 3-fold twins rotated 60° about an axis perpendicular to [001]
  
Color: White, yellowish, green, bluish white, yellowish to brownish green, brownish red
Diaphaneity: Translucent
Luster: Resinous, greasy, pearly, waxy, earthy
Hardness (Mohs): 2.5 to 3.5
Measured Density: 2.5-2.6 g/cm3
Cleavage: 3; {001} perfect, {010} and {100} distinct
Tenacity: Brittle
Fracture: Conchoidal or splintery
Streak: White
  
Polymorphism and Series: Polymorphous with clinochrysotile, lizardite, orthochrysotile, and parachrysotile.
Geologic Setting: Commonly replaces ultramafic rocks, pervasively or in crosscutting veinlets. As a
replacement of siliceous dolostone along contacts with diabase sills
Mineral Association: Chromite, magnetite, chrysotile, olivine
  
Synonyms/varieties: Bowenite, Jenkinsite, Picrolite, Picrosmine, Williamsite
Comments: Member of the kaolinite-serpentine group.

 

Antigorite
Origin: Kovdor, Kola Peninsula, Russia
Sample size: 4 x 6 cm
Photo: Diederik Visser

 

Antigorite
Antigorite pseudomorph after chondrodite with magnetite and kaolinite
Origin: Tilly Foster Mine, Brewster, Putnam County, New York, U.S.A.
Sample size: 5 x 5 x 3 cm
Photo: Rob Lavinsky

 

Antigorite
(zoom-in of above)

<<< BACK TO MINERAL SEARCH