Chloritoid Mineral Data

General Chloritoid Information

Chemical Formula:

(Fe++,Mg,Mn)2Al4Si2O10(OH)4

Composition:

Molecular Weight = 484.71 gm

Magnesium 3.01 % Mg 4.99 % MgO

Manganese 2.27 % Mn 2.93 % MnO

Aluminum 22.27 % Al 42.07 % Al₂O₃

Iron 13.83 % Fe 17.79 % FeO

Silicon 11.59 % Si 24.79 % SiO₂

Hydrogen 0.83 % H 7.43 % H₂O

Oxygen 46.21 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Fe²⁺_1.2Mg_0.6Mn²⁺_0.2Al₄Si₂O₁₀(OH)₄

Environment:

Metamorphic phyllites, schists and marbles.

IMA Status:

Valid Species (Pre-IMA) 1837

Locality:

Saas and Lukmanier, Switzerland. Link to MinDat.org Location Data.

Name Origin:

Named after its resemblance to chlorite minerals.

Synonym:

Sismondine(Mg)

Chloritoid Image

Images:

Chloritoid Paragonite

Comments: Grayish crystalline inclusion of chloritoid in white, massive paragonite.
Location: Drandorf Fundgrube Mine, Bockau, Schwarzenberg District, Erzgebirge, Saxony, Germany. Scale: Picture size 4 mm.
© Thomas Witzke / Abraxas-Verlag

Chloritoid Crystallography

Axial Ratios:

a:b:c =1.7335:1:1.6715

Cell Dimensions:

a = 9.5, b = 5.48, c = 9.16, Z = 2; alpha = 96.88°, beta = 101.8°, gamma = 90.03° V = 463.43 Den(Calc)= 3.47

Crystal System:

Triclinic - PinacoidalH-M Symbol ( 1) Space Group: P1

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

By Intensity(I/I_o): 4.47(1), 2.46(0.9), 2.97(0.8),

Crystal Structure:

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Hanscom R , American Mineralogist , 65 (1980) p.534-539, The structure of triclinic chloritoid and chloritoid polymorphism

View Additional jPOWD Structure files for Chloritoid
[1] [2] [3]

Physical Properties of Chloritoid

Cleavage:

{???} Imperfect

Color:

Green gray, Green black, Grayish black, Dark green, Dark gray.

Density:

3.52 - 3.57, Average = 3.54

Diaphaneity:

Transparent to translucent

Fracture:

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

Habit:

Foliated - Two dimensional platy forms.

Habit:

Massive - Uniformly indistinguishable crystals forming large masses.

Hardness:

6.5 - Pyrite

Luminescence:

Non-fluorescent.

Luster:

Pearly

Streak:

colorless green gray

Optical Properties of Chloritoid

Gladstone-Dale:

CI meas= 0.038 (Excellent) - where the CI = (1-KPDmeas/KC)
CI calc= 0.018 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2094,KPDmeas= 0.2049,KC= 0.2131
Ncalc = 1.74 - 1.76

Optical Data:

Biaxial (+), a=1.713-1.73, b=1.719-1.734, g=1.723-1.74, bire=0.0100, 2V(Calc)=78-80, 2V(Meas)=36-89. Dispersion r > v.

Pleochroism (x):

greenish gray, olive green, colorless, or greenish blue.

Pleochroism (y):

bluish gray, indigo, or bluish green.

Calculated Properties of Chloritoid

Electron Density:

Bulk Density (Electron Density)=3.43 gm/cc
note: Specific Gravity of Chloritoid =3.47 gm/cc.

Fermion Index:

Fermion Index = 0.01
Boson Index = 0.99

Photoelectric:

PE_Chloritoid= 5.82 barns/electron
U=PE_Chloritoid x rElectron Density= 19.95 barns/cc.

Radioactivity:

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

Chloritoid Classification

Dana Class:

52.03.03.01 (52)Nesosilicate Insular SiO4 Groups and O, OH, F, and H2O

(52.03)with cations in [6] coordination only

(52.03.03)Chloritoid group

52.03.03.01 Chloritoid (Fe,Mg,Mn)2Al4Si2O10(OH)4 P1 1

52.03.03.02 Magnesiochloritoid MgAl2SiO5(OH)2 C 2/c 2/m

52.03.03.03 Ottrelite (Mn,Fe,Mg)2Al4Si2O10(OH)4 C 2/c 2/m

52.03.03.04 Carboirite-VIII Fe(Al,Ge)2O[(Ge,Si)O4](OH)2 C1 1

Strunz Class:

09.AF.85 09 - SILICATES (Germanates)

09.A - Nesosilicates

09.AF -Nesosilicates with additional anions;

09.AF.85 Chloritoid (Fe,Mg,Mn)2Al4Si2O10(OH)4 P1 1

09.AF.85 Magnesiochloritoid MgAl2SiO5(OH)2 C 2/c 2/m

09.AF.85 Ottrelite (Mn,Fe,Mg)2Al4Si2O10(OH)4 C 2/c 2/m

Other Chloritoid Information

See Also:

Links to other databases for Chloritoid :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - Franklin Minerals(Dunn)
4 - GeoScienceWorld
5 - Google Images
6 - Google Scholar
7 - Handbook of Mineralogy (MinSocAm)
8 - Handbook of Mineralogy (UofA)
9 - MinDAT
10 - Mineralienatlas (Deutsch)
11 - Minerals in Thin Section-University of North Carolina
12 - Online Mineral Museum
13 - QUT Mineral Atlas
14 - Ruff.Info
15 - UCLA - Petrography Thin-Sections
16 - WWW-MINCRYST

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

Chloritoid

(Fe++,Mg,Mn)2Al4Si2O10(OH)4
Dana No: 52.03.03.01 Strunz No: 09.AF.85
Locality:

Notes: