Magnesiostaurolite Mineral Data

General Magnesiostaurolite Information

Chemical Formula:

[ ]4Mg4Al16(Al,[ ])2Si8O40[O6,(OH)2]

Composition:

Molecular Weight = 1,562.60 gm

Lithium 0.42 % Li 0.90 % Li₂O

Magnesium 4.70 % Mg 7.79 % MgO

Titanium 0.12 % Ti 0.20 % TiO₂

Aluminum 30.36 % Al 57.36 % Al₂O₃

Zinc 0.08 % Zn 0.10 % ZnO

Iron 0.57 % Fe 0.74 % FeO

Silicon 14.31 % Si 30.61 % SiO₂

Hydrogen 0.26 % H 2.29 % H₂O

Oxygen 49.19 % O

______ ______

100.00 % 99.99 % = TOTAL OXIDE

Empirical Formula:

Mg_0.72Fe²⁺_0.16Mg_1.85Li_0.94Zn_0.02Al_15.96Ti_0.04Al_1.58Mg_0.45Si_7.96Al_0.04O_40.04(OH)_3.98O_4.02

Environment:

Anhedral inclusions up to 250 micro-m in pyrope megablasts. Ultra-high pressure mineral.

IMA Status:

Approved IMA 2003 (Dana #Added)

Locality:

Coesite-bearing Dora-Maira massif, Italian Western Alps. Link to MinDat.org Location Data.

Name Origin:

Named as the magnesium-dominant analog of staurolite.

Synonym:

IMA1992-035

Magnesiostaurolite Image

Images:

Magnesiostaurolite

Comments: White crystals of magnesiostaurolite in rose quartz.
Location: Dora Maira Massif, Cuneo Province, Piedmont, Italy. Scale: Specimen Size 42 x 27 x 25 mm.
© Sergey Vasiliev / Systematic Mineralogy

Magnesiostaurolite Crystallography

Axial Ratios:

a:b:c =0.4758:1:0.3405

Cell Dimensions:

a = 7.8706, b = 16.5411, c = 5.6323, Z = 1; beta = 90.007° V = 733.26 Den(Calc)= 3.54

Crystal System:

Monoclinic - Prismatic H-M Symbol (2/m) Space Group: C 2/m

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

By Intensity(I/I_o): 1.968(1)(062), 1.39(0.82)(462), 2.39(0.5)(132),2.678(0.38)(151), 2.37(0.33)(330),

Physical Properties of Magnesiostaurolite

Color:

Colorless.

Diaphaneity:

Transparent

Habit:

Inclusions - Generally found as inclusions in other minerals.

Hardness:

7-7.5 - Quartz-Garnet

Luster:

Vitreous - Resinous

Streak:

white

Optical Properties of Magnesiostaurolite

Gladstone-Dale:

CI calc= 0.05 (Good) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2003,KC= 0.2109
Ncalc = 1.75

Optical Data:

Biaxial (?), b=1.709

Calculated Properties of Magnesiostaurolite

Electron Density:

Bulk Density (Electron Density)=3.50 gm/cc
note: Specific Gravity of Magnesiostaurolite =3.54 gm/cc.

Fermion Index:

Fermion Index = 0.01
Boson Index = 0.99

Photoelectric:

PE_{Magnesiostaurolite}= 1.78 barns/electron
U=PE_{Magnesiostaurolite} x rElectron Density= 6.22 barns/cc.

Radioactivity:

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

Magnesiostaurolite Classification

Dana Class:

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

(52.02)with cations in [4] and >[4] coordination

(52.02.03)Dana Group

52.02.03.01 Staurolite (Fe,Mg)2Al9(Si,Al)4O20(O,OH)4 C 2/m 2/m

52.02.03.02 Magnesiostaurolite! []4Mg4Al16(Al,[])2Si8O40[O6,(OH)2] C 2/m 2/m

52.02.03.03 Zincostaurolite! []4Zn4Al16(Al,[])2Si8O40[O6,(OH)2] C 2/m 2/m

Strunz Class:

09.AF.30 09 - SILICATES (Germanates)

09.A - Nesosilicates

09.AF -Nesosilicates with additional anions;

09.AF.30 Staurolite (Fe,Mg)2Al9(Si,Al)4O20(O,OH)4 C 2/m 2/m

09.AF.30 Magnesiostaurolite! []4Mg4Al16(Al,[])2Si8O40[O6,(OH)2] C 2/m 2/m

09.AF.30 Zincostaurolite! []4Zn4Al16(Al,[])2Si8O40[O6,(OH)2] C 2/m 2/m

Other Magnesiostaurolite Information

References:

NAME( AmMin, 88,:1626) PHYS. PROP.(AmMin, 88,:1626) OPTIC PROP.(AmMin, 88,:1626)

See Also:

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

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Magnesiostaurolite

[ ]4Mg4Al16(Al,[ ])2Si8O40[O6,(OH)2]
Dana No: 52.02.03.02 Strunz No: 09.AF.30
Locality:

Notes:

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