Magnesiogedrite Mineral Data

Magnesiogedrite Mineral Data

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General Magnesiogedrite Information

Chemical Formula:

(Mg,Fe++)5Al2Si6Al2O22(OH)2

Composition:

Molecular Weight = 847.05 gm

Magnesium 8.61 % Mg 14.27 % MgO

Aluminum 12.74 % Al 24.07 % Al₂O₃

Iron 13.19 % Fe 16.96 % FeO

Silicon 19.89 % Si 42.56 % SiO₂

Hydrogen 0.24 % H 2.13 % H₂O

Oxygen 45.33 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Mg₃Fe²⁺₂Al₂(Si₆Al₂O₂₂)(OH)₂

IMA Status:

Discredited IMA 1998

Locality:

Link to MinDat.org Location Data.

Name Origin:

Named for its composition and the original gederite location at Heas Valley, Gedres, France. IMA amphibole commission recommends abandoning this species name.

Synonym:

Discredited

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Magnesiogedrite Crystallography

Axial Ratios:

a:b:c =1.0445:1:0.2958

Cell Dimensions:

a = 18.531, b = 17.741, c = 5.249, Z = 4; V = 1,725.65 Den(Calc)= 3.26

Crystal System:

Orthorhombic - DipyramidalH-M Symbol (2/m 2/m 2/m) Space Group: P nma

Physical Properties of Magnesiogedrite

Cleavage:

[???] Good

Color:

Gray white.

Hardness:

5-6 - Between Apatite and Orthoclase

Streak:

white

Optical Properties of Magnesiogedrite

Gladstone-Dale:

CI calc= 0.071 (Fair) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1914,KC= 0.206

Optical Data:

Biaxial (-), a=1.613, b=1.625, g=1.634, bire=0.0210

Pleochroism (x):

none.

Pleochroism (y):

none.

Pleochroism (z):

none.

Calculated Properties of Magnesiogedrite

Electron Density:

r_electron=3.22 gm/cc
note: r_{Magnesiogedrite}=3.26 gm/cc.

Fermion Index

Fermion Index = 0.02091
Boson Index = 0.97909

Photoelectric:

PE_{Magnesiogedrite}= 5.22 barns/electron
U=PE_{Magnesiogedrite} x r_electron= 16.80 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Magnesiogedrite is Not Radioactive

Magnesiogedrite Classification

Dana Class:

66.1.2.5 (66)Inosilicate Double-Width Unbranched Chains, W=2

(66.1)Dana Type

(66.1.2)Group 1, the Mg-Fe-Mn-Li amphiboles (Orthorhombic)

66.1.2.1 Magnesioanthophyllite? (Mg,Fe)7Si8O22(OH)2 P nma 2/m 2/m 2/m

66.1.2.2 Anthophyllite []Mg7Si8O22(OH)2 P nma 2/m 2/m 2/m

66.1.2.2a Protoanthophyllite! (Mg,Fe)7Si8O22(OH)2 Pnmn 2/m 2/m 2/m

66.1.2.3 Ferro-anthophyllite []Fe7Si8O22(OH)2 P nma 2/m 2/m 2/m

66.1.2.3a Protoferro-anthophyllite! (Fe,Mn)2(Fe,Mg)5(Si4O11)2(OH)2 Pnmn 2/m 2/m 2/m

66.1.2.3b Protomangano-ferro-anthophyllite! (Mn,Fe)2(Fe,Mg)5(Si4O11)2(OH)2 Pnmn 2/m 2/m 2/m

66.1.2.4 Sodicanthophyllite NaMg7Si8O22(OH)2 P nma 2/m 2/m 2/m

66.1.2.4a Sodic-ferro-anthophyllite! NaFe7Si8O22(OH)2 P nma 2/m 2/m 2/m

66.1.2.5 Magnesiogedrite ? (Mg,Fe)5Al2Si6Al2O22(OH)2 P nma 2/m 2/m 2/m

66.1.2.6 Gedrite []Mg5Al2Si6Al2O22(OH)2 P nma 2/m 2/m 2/m

66.1.2.7 Ferrogedrite []Fe5Al2Si6Al2O22(OH)2 P nma 2/m 2/m 2/m

66.1.2.7a Sodic-ferrogedrite! NaFe6AlSi6Al2O22(OH)2 P nma 2/m 2/m 2/m

66.1.2.8 Sodicgedrite NaMg6AlSi6Al2O22(OH)2 P nma 2/m 2/m 2/m

66.1.2.9 Magnesioholmquistite Li2(Mg,Fe)3Al2Si8O22(OH)2 P nma 2/m 2/m 2/m

66.1.2.10 Holmquistite [](Li2Mg3Al2)Si8O22(OH)2 P nma 2/m 2/m 2/m

66.1.2.11 Ferroholmquistite [](Li2Fe3Al2)Si8O22(OH)2 P nma 2/m 2/m 2/m

66.1.2.12 IMA2004-030! []Li2(Fe3Al2)S5(Si8O22)(OH)2 P nma 2/m 2/m 2/m

Strunz Class:

VIII/F.12-90 VIII - Silicates

VIII/F - Inosilicates (chain and band) double chains [Si4O11]6-, Orthorhombic Amphiboles

VIII/F.12 - Amphibole group, Magnesioholmquistite - Ferrogedrite series

VIII/F.12-10 Magnesioholmquistite Li2(Mg,Fe)3Al2Si8O22(OH)2 P nma 2/m 2/m 2/m

VIII/F.12-20 Holmquistite [](Li2Mg3Al2)Si8O22(OH)2 P nma 2/m 2/m 2/m

VIII/F.12-30 Ferroholmquistite [](Li2Fe3Al2)Si8O22(OH)2 P nma 2/m 2/m 2/m

VIII/F.12-40 Sodicanthophyllite NaMg7Si8O22(OH)2 P nma 2/m 2/m 2/m

VIII/F.12-45 Sodic-ferro-anthophyllite! NaFe7Si8O22(OH)2 P nma 2/m 2/m 2/m

VIII/F.12-50 Magnesioanthophyllite? (Mg,Fe)7Si8O22(OH)2 P nma 2/m 2/m 2/m

VIII/F.12-60 Anthophyllite []Mg7Si8O22(OH)2 P nma 2/m 2/m 2/m

VIII/F.12-70 Ferro-anthophyllite []Fe7Si8O22(OH)2 P nma 2/m 2/m 2/m

VIII/F.12-75 Sodic-ferrogedrite! NaFe6AlSi6Al2O22(OH)2 P nma 2/m 2/m 2/m

VIII/F.12-80 Sodicgedrite NaMg6AlSi6Al2O22(OH)2 P nma 2/m 2/m 2/m

VIII/F.12-90 Magnesiogedrite (Mg,Fe)5Al2Si6Al2O22(OH)2 P nma 2/m 2/m 2/m

VIII/F.12-100 Gedrite []Mg5Al2Si6Al2O22(OH)2 P nma 2/m 2/m 2/m

VIII/F.12-110 Ferrogedrite []Fe5Al2Si6Al2O22(OH)2 P nma 2/m 2/m 2/m

VIII/F.12-130 Protoferro-anthophyllite! (Fe,Mn)2(Fe,Mg)5(Si4O11)2(OH)2 Pnmn 2/m 2/m 2/m

VIII/F.12-140* Protoanthophyllite! (Mg,Fe)7Si8O22(OH)2 Pnmn 2/m 2/m 2/m

VIII/F.12-140 Protomangano-ferro-anthophyllite! (Mn,Fe)2(Fe,Mg)5(Si4O11)2(OH)2 Pnmn 2/m 2/m 2/m

Other Magnesiogedrite Information

References:

NAME( Dana8) PHYS. PROP.(Dana8) OPTIC PROP.(Dana8)

See Also:

Links to other databases for Magnesiogedrite :
1 -Am. Min. Crystal Structure Database 2 -Athena 3 - EUROmin Project 4 -Google Images 5 -Google Scholar 6 -MinDAT 7 -MinMax(Deutsch) 8 -MinMax(English) 9 -Mineralienatlas (Deutsch) 10 -QUT Mineral Atlas 11 -École des Mines de Paris

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Magnesiogedrite

(Mg,Fe++)5Al2Si6Al2O22(OH)2
Dana No: 66.1.2.5 Strunz No: VIII/F.12-90
Locality:

Notes: