Magnesiocummingtonite Mineral Data

Magnesiocummingtonite Mineral Data

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General Magnesiocummingtonite Information

Chemical Formula:

(Mg,Fe++)7Si8O22(OH)2

Composition:

Molecular Weight = 836.02 gm

Magnesium 15.26 % Mg 25.31 % MgO

Iron 11.69 % Fe 15.04 % FeO

Silicon 26.88 % Si 57.50 % SiO₂

Hydrogen 0.24 % H 2.15 % H₂O

Oxygen 45.93 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Mg_5.25Fe²⁺_1.75Si₈O₂₂(OH)₂

IMA Status:

Approved IMA 1969

Locality:

Link to MinDat.org Location Data.

Synonym:

ICSD 41925

PDF 17-727

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Magnesiocummingtonite Crystallography

Crystal System:

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

Physical Properties of Magnesiocummingtonite

Cleavage:

[110] Good

Color:

Brown, Gray green, White, Light gray, Dark green.

Density:

3.13

Hardness:

5-6 - Between Apatite and Orthoclase

Luster:

Silky

Streak:

white

Optical Properties of Magnesiocummingtonite

Optical Data:

NCalc= 1.64 - from Gladstone-Dale relationship (KC = 0.2058) where Ncalc=Dmeas*KC+1

Calculated Properties of Magnesiocummingtonite

Electron Density:

r_electron=3.10 gm/cc
note: r_{Magnesiocummingtonite}=3.13 gm/cc.

Fermion Index

Fermion Index = 0.03051
Boson Index = 0.96949

Photoelectric:

PE_{Magnesiocummingtonite}= 4.81 barns/electron
U=PE_{Magnesiocummingtonite} x r_electron= 14.92 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Magnesiocummingtonite is Not Radioactive

Magnesiocummingtonite Classification

Dana Class:

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

(66.1)Dana Type

(66.1.1)Group 1, the Mg-Fe-Mn-Li amphiboles (Monoclinic)

66.1.1.1 Magnesiocummingtonite (Mg,Fe)7Si8O22(OH)2 C 2/m 2/m

66.1.1.2 Cummingtonite []Mg7Si8O22(OH)2 C 2/m 2/m

66.1.1.3 Grunerite []Fe7Si8O22(OH)2 C 2/m 2/m

66.1.1.3b Permanganogrunerite! []Mn4(Fe)3(Si8O22)(OH)2 C 2/m 2/m

66.1.1.4 Manganocummingtonite Na(Na,Mn)2(Mg4,Fe)5Si8O22(OH)2 C 2/m 2/m

66.1.1.5 Manganogrunerite []Mn2Fe5Si8O22(OH) C 2/m 2/m

66.1.1.6 Magnesioclinoholmquistite? Li2(Mg,Fe)3Al2Si8O22(OH)2 C 2/m 2/m

66.1.1.7 Clinoholmquistite? [](Li2Mg3Al2)Si8O22(OH)2 C 2/m 2/m

66.1.1.8 Clinoferroholmquistite [](Li2Fe3Al2)Si8O22(OH)2 C 2/m 2/m

66.1.1.8a Ferri-clinoholmquistite! []Li2Mg3(Fe3)2(Si8O22)(OH)2 C 2/m 2/m

66.1.1.8b Ferri-clinoferroholmquistite! []Li2(Fe2Fe3)Si8O22(OH)2 C 2/m 2/m

66.1.1.9 Sodic-ferripedrizite! Na(LiNa)(Fe2Mg2Li)Si8O22(OH,F)2 C 2/m 2/m

66.1.1.9a Ferripedrizite! NaLi2(Fe2Mg2Li)Si8O22(OH)2 C 2/m 2/m

66.1.1.9b Sodic-ferri-ferropedrizite! NaLi2(Fe2Fe3)Si8O22(OH)2 C 2/m 2/m

66.1.1.9c Fluoro-sodic-pedrizite! NaLi2(Mg2Al2Li)S5Si8O22F2 C 2/m 2/m

Strunz Class:

VIII/F.07-10 VIII - Silicates

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

VIII/F.07 - Amphibole group, Magnesiocummingtonite - Ferroclinoholmquistite series

VIII/F.07-10 Magnesiocummingtonite (Mg,Fe)7Si8O22(OH)2 C 2/m 2/m

VIII/F.07-20 Cummingtonite []Mg7Si8O22(OH)2 C 2/m 2/m

VIII/F.07-30 Grunerite []Fe7Si8O22(OH)2 C 2/m 2/m

VIII/F.07-40 Manganocummingtonite Na(Na,Mn)2(Mg4,Fe)5Si8O22(OH)2 C 2/m 2/m

VIII/F.07-50 Manganogrunerite []Mn2Fe5Si8O22(OH) C 2/m 2/m

VIII/F.07-55 Permanganogrunerite! []Mn4(Fe)3(Si8O22)(OH)2 C 2/m 2/m

VIII/F.07-60 Magnesioclinoholmquistite? Li2(Mg,Fe)3Al2Si8O22(OH)2 C 2/m 2/m

VIII/F.07-70 Clinoholmquistite? [](Li2Mg3Al2)Si8O22(OH)2 C 2/m 2/m

VIII/F.07-80 Clinoferroholmquistite [](Li2Fe3Al2)Si8O22(OH)2 C 2/m 2/m

VIII/F.07-90 Ferri-clinoferroholmquistite! []Li2(Fe2Fe3)Si8O22(OH)2 C 2/m 2/m

Other Magnesiocummingtonite Information

See Also:

Links to other databases for Magnesiocummingtonite :
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 -École des Mines de Paris

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

Magnesiocummingtonite

(Mg,Fe++)7Si8O22(OH)2
Dana No: 66.1.1.1 Strunz No: VIII/F.07-10
Locality:

Notes: