Antigorite Mineral Data

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General Antigorite Information

Chemical Formula:

(Mg,Fe++)3Si2O5(OH)4

Composition:

Molecular Weight = 300.77 gm

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

Empirical Formula:

Mg_2.25Fe²⁺_0.75(Si₂O₅)(OH)₄

Environment:

Common in regional and contact metamorphosed serpentinites

IMA Status:

Valid Species (Pre-IMA) 1840

Locality:

Antigorio, Italy Link to MinDat.org Location Data.

Name Origin:

Named after its locality. From the Latin, serpens - "snake."

Name Pronunciation:

Antigorite + Pronunciation

Synonym:

Bowenite

Jenkinsite

Picrosmine

Protoantigorite

Williamsite

Antigorite Image

Images:

Antigorite

Comments: Yellowish green, fibrous antigorite.
Location: East Broughon, Quebec, Canada. Scale: 22x10 cm.
© Dave Barthelmy

Images:

Antigorite Chromite

Comments: Chromite veins in yellow to green antigorite with picrolite, chromian antigorite and dolomite (polished section).
Location: Wood's Mine, near 'Texas', Little Britain Township, Lancaster County, Pennsylvania, USA. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Antigorite Crystallography

Axial Ratios:

a:b:c =4.7013:1:0.7844

Cell Dimensions:

a = 43.53, b = 9.259, c = 7.263, Z = 16; beta = 91.633° V = 2,926.12 Den(Calc)= 2.73

Crystal System:

Monoclinic - DomaticH-M Symbol (m) Space Group: Cm

$Help on X Ray Diffraction:$ X Ray Diffraction:

By Intensity(I/I_o): 2.53(1), 7.29(1), 3.61(0.8),

Crystal Structure:

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Capitani G , Mellini M , American Mineralogist , 89 (2004) p.147-158, The modulated crystal structure of antigorite: The m = 17 polysome

View Additional jPOWD Structure files for Antigorite
[1] [2]

Physical Properties of Antigorite

Cleavage:

{001} Good

Color:

Green, Gray, Bluish gray, Brown, Black.

Density:

2.5 - 2.6, Average = 2.54

Diaphaneity:

Translucent to Subopaque

Fracture:

Brittle - Generally displayed by glasses and most non-metallic minerals.

Habit:

Massive - Uniformly indistinguishable crystals forming large masses.

Habit:

Platy - Sheet forms (e.g. micas).

Habit:

Scaly - Morphology like fish scales.

Hardness:

3.5-4 - Copper Penny-Fluorite

Luster:

Vitreous - Greasy

Streak:

greenish white

Optical Properties of Antigorite

Gladstone-Dale:

CI meas= -0.017 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= 0.05 (Good) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2068,KPDmeas= 0.2214,KC= 0.2178
Ncalc = 1.54 - 1.59

Optical Data:

Biaxial (-), a=1.555-1.567, b=1.56-1.573, g=1.56-1.573, bire=0.0050-0.0060, 2V(Calc)=0, 2V(Meas)=20-50. Dispersion weak, r > v.

Pleochroism (x):

pale greenish yellow.

Pleochroism (y):

light green.

Pleochroism (z):

light green.

Calculated Properties of Antigorite

Electron Density:

Bulk Density (Electron Density)=2.55 gm/cc
note: Specific Gravity of Antigorite =2.55 gm/cc.

Fermion Index:

Fermion Index = 0.03
Boson Index = 0.97

Photoelectric:

PE_Antigorite= 5.20 barns/electron
U=PE_Antigorite x rElectron Density= 13.27 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Antigorite is Not Radioactive

Antigorite Classification

Dana Class:

71.01.02a.01 (71)Phyllosilicate Sheets of Six-Membered Rings

(71.01)with 1:1 layers

(71.01.02a)Serpentine group

71.01.02a.01 Antigorite (Mg,Fe)3Si2O5(OH)4 Cm m

Strunz Class:

09.ED.15 09 - SILICATES (Germanates)

09.E - Phyllosilicates

09.ED -Phyllosilicates with kaolinite layers

09.ED.15 Clinochrysotile? Mg3Si2O5(OH)4 Cc, C 2/m Mono

09.ED.15 Berthierine (Fe,Fe,Al,Mg)2-3(Si,Al)2O5(OH)4 Cm m

09.ED.15 Brindleyite (Ni,Mg,Fe)2Al(SiAl)O5(OH)4 C 2 2

09.ED.15 Amesite Mg2Al(SiAl)O5(OH)4 C1 1

09.ED.15 Antigorite (Mg,Fe)3Si2O5(OH)4 Cm m

09.ED.15 Caryopilite (Mn,Mg,Zn,Fe)3(Si,As)2O510(OH,Cl)4 Cm or C 2/m Mono

09.ED.15 Fraipontite (Zn,Al)3(Si,Al)2O5(OH)4 Cm m

09.ED.15 Cronstedtite Fe2Fe(SiFe)O5(OH)4 P 3₁m 3m

09.ED.15 Chrysotile Mg3Si2O5(OH)4 A2/m 2/m

09.ED.15 Nepouite Ni3Si2O5(OH)4 Ccm21 mm2

09.ED.15 Greenalite (Fe,Fe)2-3Si2O5(OH)4 Unk Mono

09.ED.15 Kellyite (Mn,Mg,Al)3(Si,Al)2O5(OH)4 P 6₃ 6

09.ED.15 Maufite? (Mg,Ni)Al4Si3O13•4(H2O)(?) Mono ? Mono

09.ED.15 Lizardite Mg3Si2O5(OH)4 P1 1

09.ED.15 Orthochrysotile? Mg3Si2O5(OH)4 Unk Ortho

09.ED.15 Manandonite Li2Al4[(Si2AlB)O10](OH)8 C1 1

09.ED.15 Pecoraite Ni3Si2O5(OH)4 C 2/m 2/m

09.ED.15 Parachrysotile? Mg3Si2O5(OH)4 Unk Ortho

Other Antigorite Information

References:

NAME( Dana8) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Heinrich65)

See Also:

Links to other databases for Antigorite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - EUROmin Project
4 - Ecole des Mines de Paris
5 - GeoScienceWorld
6 - Google Images
7 - Google Scholar
8 - Handbook of Mineralogy (MinSocAm)
9 - Handbook of Mineralogy (UofA)
10 - HyperPhysics
11 - MinDAT
12 - Mineralienatlas (Deutsch)
13 - Online Mineral Museum
14 - QUT Mineral Atlas
15 - Ruff.Info
16 - WWW-MINCRYST

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Ask about Antigorite here :
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Print or Cut-and-Paste your Antigorite Specimen Label here :

Antigorite

(Mg,Fe++)3Si2O5(OH)4
Dana No: 71.01.02a.01 Strunz No: 09.ED.15
Locality:

Notes: