Magnesiodumortierite Mineral Data

General Magnesiodumortierite Information

Chemical Formula:

(Mg,Ti,[ ])<1(Al,Mg)2Al4Si3O18-y(OH)yB y=2-3

Composition:

Molecular Weight = 572.14 gm

Magnesium 4.25 % Mg 7.04 % MgO

Titanium 2.51 % Ti 4.19 % TiO₂

Aluminum 25.94 % Al 49.01 % Al₂O₃

Silicon 14.73 % Si 31.51 % SiO₂

Boron 1.89 % B 6.08 % B₂O₃

Hydrogen 0.35 % H 3.15 % H₂O

Oxygen 50.34 % O

______ ______

100.00 % 100.98 % = TOTAL OXIDE

Empirical Formula:

MgTi_0.3Al_5.5Si₃O₁₆B(OH)₂

Environment:

In pyrope megablasts which occur in coesite bearing quartz-phengite-kyanite schists.

IMA Status:

Approved IMA 1995

Locality:

Dor-Maira massif, western Alps, Italy. Link to MinDat.org Location Data.

Name Origin:

For its containing magnesium and the relationship to dumortierite.

Synonym:

ICSD 79840

IMA1992-050

PDF 47-1876

Magnesiodumortierite Crystallography

Axial Ratios:

a:b:c =0.5832:1:0.2308

Cell Dimensions:

a = 11.91, b = 20.42, c = 4.714, Z = 4; V = 1,146.46 Den(Calc)= 3.31

Crystal System:

Orthorhombic - Dipyramidal H-M Symbol (2/m 2/m 2/m) Space Group: Pmcn

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

By Intensity(I/I_o): 3.246(1), 2.105(0.9), 5.91(0.9),

Physical Properties of Magnesiodumortierite

Cleavage:

{001} Poor

Color:

Pinkish red, Red.

Density:

3.22

Diaphaneity:

Transparent

Habit:

Disseminated - Occurs in small, distinct particles dispersed in matrix.

Hardness:

7.5 - Garnet

Luminescence:

Non-fluorescent.

Luster:

Vitreous (Glassy)

Streak:

white

Optical Properties of Magnesiodumortierite

Gladstone-Dale:

CI meas= 0.028 (Excellent) - where the CI = (1-KPDmeas/KC)
CI calc= 0.054 (Good) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2094,KPDmeas= 0.2152,KC= 0.2213
Ncalc = 1.71 - 1.73

Optical Data:

Biaxial (-), a=1.678, b=1.7, g=1.701, bire=0.0230, 2V(Calc)=22, 2V(Meas)=38.5.

Pleochroism (x):

red or pale pink.

Pleochroism (y):

colorless or colorless.

Pleochroism (z):

colorless or colorless.

Calculated Properties of Magnesiodumortierite

Electron Density:

Bulk Density (Electron Density)=3.19 gm/cc
note: Specific Gravity of Magnesiodumortierite =3.22 gm/cc.

Fermion Index:

Fermion Index = 0.01
Boson Index = 0.99

Photoelectric:

PE_{Magnesiodumortierite}= 1.85 barns/electron
U=PE_{Magnesiodumortierite} x rElectron Density= 5.89 barns/cc.

Radioactivity:

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

Magnesiodumortierite Classification

Dana Class:

54.01.02.02 (54)Nesosilicate Borosilicates and Some Beryllosilicates

(54.01)with (BO3)

(54.01.02)Dumortierite group

54.01.02.01 Dumortierite Al6.5-7(BO3)(SiO4)3(O,OH)3 Pcmn 2/m 2/m 2/m

54.01.02.02 Magnesiodumortierite (Mg,Ti,[])<1(Al,Mg)2Al4Si3O18-y(OH)yBy=2-3 Pmcn 2/m 2/m 2/m

Strunz Class:

09.AJ.10 09 - SILICATES (Germanates)

09.A - Nesosilicates

09.AJ -Nesosilicates with BO3 triangles and/or B[4], Be[4] tetrahedra,

09.AJ.10 Dumortierite Al6.5-7(BO3)(SiO4)3(O,OH)3 Pcmn 2/m 2/m 2/m

09.AJ.10 Holtite Al6(Al,Ta)(BO3)[(SiO4,SbO4,AsO4)]3(O,OH)3 P nma 2/m 2/m 2/m

09.AJ.10 Magnesiodumortierite (Mg,Ti,[])<1(Al,Mg)2Al4Si3O18-y(OH)yBy=2-3 Pmcn 2/m 2/m 2/m

Other Magnesiodumortierite Information

References:

NAME( MinRec) PHYS. PROP.(Am.Min.,Vol.81,1996) OPTIC PROP.(MinRec)

See Also:

Links to other databases for Magnesiodumortierite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - Diederik Visser
4 - GeoScienceWorld
5 - Google Images
6 - Google Scholar
7 - MinDAT
8 - Mineralienatlas (Deutsch)
9 - Online Mineral Museum
10 - QUT Mineral Atlas
11 - Ruff.Info
12 - WWW-MINCRYST

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Magnesiodumortierite

(Mg,Ti,[ ])<1(Al,Mg)2Al4Si3O18-y(OH)yB y=2-3
Dana No: 54.01.02.02 Strunz No: 09.AJ.10
Locality:

Notes:

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