Magnesiochloritoid Mineral Data

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General Magnesiochloritoid Information

Chemical Formula:

MgAl2SiO5(OH)2

Composition:

Molecular Weight = 220.37 gm

Magnesium 11.03 % Mg 18.29 % MgO

Aluminum 24.49 % Al 46.27 % Al₂O₃

Silicon 12.74 % Si 27.27 % SiO₂

Hydrogen 0.91 % H 8.18 % H₂O

Oxygen 50.82 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

MgAl₂SiO₅(OH)₂

Environment:

In metapelites and related rocks within high-grade blueschist rocks; stable under metamorphic conditions of near 500 ±C and 18 kbar.

IMA Status:

Approved IMA 1983

Locality:

Monte Rosa massif, near the Ghiacciaio di Verra; in the Val d'Ayas, Italy, near the border with Switzerland. Link to MinDat.org Location Data.

Name Origin:

Named for magnesium in its composition and its relation to chloritoid.

Synonym:

Sismondine

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Magnesiochloritoid Crystallography

Axial Ratios:

a:b:c =1.7291:1:3.3233

Cell Dimensions:

a = 9.46, b = 5.471, c = 18.182, Z = 9; beta = 101.4° V = 922.46 Den(Calc)= 3.57

Crystal System:

Monoclinic - PrismaticH-M Symbol (2/m) Space Group: C 2/c

$Help on X Ray Diffraction:$ 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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Ivaldi G , Catti M , Ferraris G , American Mineralogist , 73 (1988) p.358-364, Crystal structure at 25 and 700 C of magnesiochloritoid from a high-pressure, assemblage (Monte Rosa), Sample at 25 C

View Additional jPOWD Structure files for Magnesiochloritoid
[1] [2] [3] [4]

Physical Properties of Magnesiochloritoid

Cleavage:

{001} Perfect, {110} Distinct

Color:

Greenish gray, Greenish black.

Density:

3.5 - 3.6, Average = 3.55

Diaphaneity:

Translucent

Hardness:

6.5 - Pyrite

Luster:

Pearly

Streak:

gray white

Optical Properties of Magnesiochloritoid

Gladstone-Dale:

CI meas= 0.065 (Fair) - where the CI = (1-KPDmeas/KC)
CI calc= 0.07 (Fair) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2017,KPDmeas= 0.2028,KC= 0.2169
Ncalc = 1.76 - 1.78

Optical Data:

Biaxial (?), b=1.72

Calculated Properties of Magnesiochloritoid

Electron Density:

Bulk Density (Electron Density)=3.54 gm/cc
note: Specific Gravity of Magnesiochloritoid =3.55 gm/cc.

Fermion Index:

Fermion Index = 0.01
Boson Index = 0.99

Photoelectric:

PE_{Magnesiochloritoid}= 1.47 barns/electron
U=PE_{Magnesiochloritoid} x rElectron Density= 5.20 barns/cc.

Radioactivity:

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

Magnesiochloritoid Classification

Dana Class:

52.03.03.02 (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 Magnesiochloritoid Information

References:

NAME( AntBidBlaNic2) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990)

See Also:

Links to other databases for Magnesiochloritoid :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - Google Images
4 - Google Scholar
5 - Handbook of Mineralogy (MinSocAm)
6 - Handbook of Mineralogy (UofA)
7 - MinDAT
8 - MinMax(Deutsch)
9 - MinMax(English)
10 - Mineralienatlas (Deutsch)
11 - QUT Mineral Atlas
12 - Ruff.Info
13 - WWW-MINCRYST

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Print or Cut-and-Paste your Magnesiochloritoid Specimen Label here :

Magnesiochloritoid

MgAl2SiO5(OH)2
Dana No: 52.03.03.02 Strunz No: 09.AF.85
Locality:

Notes: