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Antigorite
Current inventory:  0 gems
 

Antigorite

  
Antigorite is named after its discovery locality of Valle di Antigorio
, Domodossola, Piedmont, Italy.

Discovered in 1840;   IMA status:  Valid (pre-IMA; Grandfathered)

 

Chemistry

 

 

Chemical Formula:

(Mg;Fe2+)3Si2O5(OH)4

 

Magnesium Iron Silicate Hydroxide

Molecular Weight:

300.77 gm

Composition:

Magnesium

18.18 %

Mg

30.15 %

MgO

 

Iron

13.93 %

Fe

17.92 %

FeO

 

Silicon

18.68 %

Si

39.95 %

SiO2

 

Hydrogen

1.34 %

H

11.98 %

H2O

 

Oxygen

47.88 %

O

 

 

 

 

100.00 %

 

100.00 %

= TOTAL OXIDE

 

 

Classification

   

   

Mineral Classification:

Silicates (Germanates)

Strunz 8th Ed. ID:

8/H.27-10

Nickel-Strunz 10th Ed. ID:

9.ED.15

 

9 : SILICATES (Germanates)
E : Phyllosilicates
D : Phyllosilicates with kaolinite layers composed of tetrahedral and octahedral nets

Related to:

Serpentine Group (also known as Kaolinite-Serpentine Group). Polymorphous with Clinochrysotile, Lizardite, Orthochrysotile, and Parachrysotile.

Members of Group:

Serpentine Group (also known as Kaolinite-Serpentine Group): Amesite, Antigorite, Berthierine, Brindleyite, Caryopilite, Chrysotile, Clinochrysotile, Cronstedite, Dickite, Fraipontite, Greenalite, Halloysite, Kaolinite, Kellyite, Lizardite, Manandonite, Nacrite, Népouite, Odinite, Orthochrysotile, Parachrysotile, Pecoraite

Varieties:

Al-Antigorite, Andes Jade, Bowenite, Jenkinsite, Picrolite

Synonyms:

Baltimorite, Bastard Asbestos, Genthite, Gymnite, Iron-Gymnite, Nickel-Gymnite, Porcellophite, Protoantigorite, Septeantigorite, Thermophyllite, Williamsite, Yu yen shi stone, Yu yen stone, Zermattite

 

 

Crystal Data

   

   

Crystallography:

Monoclinic - Domatic

Crystal Habit:

Minute crystals, typically platy along [001], rarely elongated along [010]; some plates have rectangular outline due to cleavage; commonly bladed or fibrous.

Twinning:

May exhibit two- or three-fold twins rotated 60° about an axis [001].

 

 

Physical Properties

   

 

Cleavage:

Perfect on {001}, observed on {100} and {010}

Fracture:

Conchoidal or Splintery

Tenacity:

Brittle

Moh's Hardness:

3.5 - 4.0

Density:

2.50 - 2.60 (g/cm3)

Luminescence:

None

Radioactivity:

Not Radioactive

 

 

Optical Properties

   

   

Color:

Green, Blue-Green, White; Colorless to pale Green in thin section.

Transparency:

Translucent to Sub-Opaque

Luster:

Resinous, Greasy, Silky, Waxy, Earthy

Refractive Index:

1.555 - 1.573  Biaxial ( - )

Birefringence:

0.005 - 0.006

Dispersion:

Weak; r > v

Pleochroism:

None

 

 

Occurances

   

   

Geological Setting:

Commonly replaces ultramafic rocks, pervasively or in crosscutting veinlets. As a replacement of siliceous dolostone along contacts with diabase sills.

Common Associations:

Chromite, Chrysotile, Magnetite, Olivine

Common Impurities:

Ni, Al, Mn

Type Locality:

Antigorio Valley, Ossola Valley, Verbano-Cusio-Ossola Province, Piedmont, Italy; Geisspfad area, Binn Valley, Wallis (Valais), Switzerland

Year Discovered:

1840

View mineral photos:

Antigorite Mineral Photos and Locations

 

 

More Information

   

   

 

Mindat.org
Webmineral.com

 

 


Antigorite is a member of the Serpentine group of minerals that also includes Bowenite, Lizardite and
Williamsite. Most Antigorite is opaque and fibrous but a few locations produce beautiful, translucent, pale green material suitable for cabochons or carvings and rarely even faceted gems. Examples of this gemmy, translucent material from the Pennsylvania-Maryland border area are often referred to as Williamsite.

Sources of Antigorite include the type locality; Antigorio Valley, Piedmont, Italy; New South Wales, Australia; Tirol Austria; Liaoning Province, China; Nagasaki and Fukuoka Prefectures, Japan; Glen Urquhart, Scotland; and in the USA at Texas, Pennsylvania; Baltimore, Maryland; and Brewster, New York. Most of these locations produce opaque, fibrous material not suitable for faceted gems or cabochons.
 

  
Antigorite gems for sale:

Antigorite-001

Gem:

Antigorite

Stock #:

ANTIG-001

Weight:

3.2050 ct

Size:

11.05 x 9.06 x 4.27 mm

Shape:

Oval Cabochon

Color:

Pale Green

Clarity:

Translucent

Origin:

China

Treatment:

None (natural)

Price:

SOLD (but we have others)

Pictures are of the actual gem offered for sale.
Gem images are magnified to show detail.

Antigorite-001

A beautiful pale green gem from China with a high polish and glowing color.

 

 


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