Magnesioriebeckite Mineral Data

General Magnesioriebeckite Information

Chemical Formula:

[ ]Na2[(Mg,Fe++)3Fe+++2]Si8O22(OH)2

Composition:

Molecular Weight = 876.08 gm

Potassium 0.13 % K 0.16 % K₂O

Sodium 4.09 % Na 5.52 % Na₂O

Calcium 1.97 % Ca 2.75 % CaO

Magnesium 5.35 % Mg 8.88 % MgO

Titanium 0.16 % Ti 0.27 % TiO₂

Manganese 0.31 % Mn 0.45 % Mn₂O₃

Aluminum 0.80 % Al 1.51 % Al₂O₃

Iron 17.47 % Fe 12.06 % FeO / 11.57 % Fe₂O₃

Silicon 25.65 % Si 54.87 % SiO₂

Hydrogen 0.23 % H 2.06 % H₂O

Oxygen 43.83 % O

______ ______

100.00 % 100.10 % = TOTAL OXIDE

Empirical Formula:

Na_1.56Ca_0.43K_0.03Mg_1.93Fe²⁺_1.47Fe³⁺_1.27Al_0.26Mn³⁺_0.05Ti_0.03(Si₈O₂₂)(OH)₂

Environment:

Sodium-rich igneous and metamorphic rocks.

IMA Status:

Valid Species (Pre-IMA) 1957

Locality:

Socotra island, Indian Ocean, Yemen. Link to MinDat.org Location Data.

Name Origin:

Named for the composition and relatinship to riebeckite.

Magnesioriebeckite Image

Images:

Magnesioriebeckite

Comments: Crystal of magnesioriebeckite showing massive and asbestosform habits.
Location: Cochabamba Dept, Bolivia. Scale: 2.5 cm.
© John Attard

Magnesioriebeckite Crystallography

Axial Ratios:

a:b:c =0.5448:1:0.291

Cell Dimensions:

a = 9.801, b = 17.988, c = 5.235, Z = 2; beta = 104.984° V = 891.55 Den(Calc)= 3.26

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): 8.45(1), 3.12(0.9), 2.89(0.6),

Physical Properties of Magnesioriebeckite

Cleavage:

{110} Perfect

Color:

Light blue, Dark blue, Black, Black blue.

Density:

3.19

Diaphaneity:

Translucent to Subopaque

Fracture:

Brittle - Uneven - Very brittle fracture producing uneven fragments.

Habit:

Acicular - Occurs as needle-like crystals.

Habit:

Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline).

Hardness:

5 - Apatite

Luster:

Vitreous - Silky

Streak:

blue gray

Optical Properties of Magnesioriebeckite

Gladstone-Dale:

CI meas= 0.041 (Good) - where the CI = (1-KPDmeas/KC)
CI calc= 0.062 (Fair) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2065,KPDmeas= 0.2111,KC= 0.2201
Ncalc = 1.7 - 1.72

Optical Data:

Biaxial (-), a=1.668, b=1.672, g=1.68, bire=0.0120, 2V(Calc)=72, 2V(Meas)=75-85.

Calculated Properties of Magnesioriebeckite

Electron Density:

Bulk Density (Electron Density)=3.15 gm/cc
note: Specific Gravity of Magnesioriebeckite =3.19 gm/cc.

Fermion Index:

Fermion Index = 0.02
Boson Index = 0.98

Photoelectric:

PE_{Magnesioriebeckite}= 6.72 barns/electron
U=PE_{Magnesioriebeckite} x r_electron= 21.14 barns/cc.

Radioactivity:

GRapi = 1.93 (Gamma Ray American Petroleum Institute Units)
Concentration of Magnesioriebeckite per GRapi unit = 51.93 (%)

Estimated Radioactivity from Magnesioriebeckite - barely detectable

Magnesioriebeckite Classification

Dana Class:

66.01.03c.04 (66)Inosilicate Double-Width Unbranched Chains, W=2

(66.01)with P=2 amphibole configuration

(66.01.03c)Group 4, the sodic amphiboles

66.01.03c.01 Glaucophane []Na2(Mg3Al2)Si8O22(OH)2 C 2/m 2/m

66.01.03c.02 Ferroglaucophane []Na2(Fe3Al2)Si8O22(OH)2 C 2/m 2/m

66.01.03c.03 Crossite? Na2(Mg,Fe)3(Al,Fe)2Si8O22(OH)2 C 2/m 2/m

66.01.03c.04 Magnesioriebeckite []Na2[(Mg,Fe)3Fe2]Si8O22(OH)2 C 2/m 2/m

66.01.03c.05 Riebeckite []Na2(Fe3Fe2)Si8O22(OH)2 C 2/m 2/m

66.01.03c.06 Eckermannite NaNa2(Mg4Al)Si8O22(OH)2 C 2/m 2/m

66.01.03c.07 Ferro-eckermannite NaNa2(Fe4Al)Si8O22(OH)2 C 2/m 2/m

66.01.03c.08 Magnesio-arfvedsonite NaNa2(Mg4Fe)Si8O22(OH)2 C 2/m 2/m

66.01.03c.09 Arfvedsonite NaNa2(Fe4Fe)Si8O22(OH)2 C 2/m 2/m

66.01.03c.09a Fluoro-magnesio-arfvedsonite! NaNa2(Mg,Fe)4Fe[Si8O22](F,OH)2 C 2/m 2/m

66.01.03c.09b Potassicarfvedsonite! KNa2Fe4FeSi8O22(OH)2 C 2/m 2/m

66.01.03c.10 Kozulite NaNa2Mn4(Fe,Al)Si8O22(OH)2 C 2/m 2/m

66.01.03c.11 Nyboite NaNa2(Mg3Al2)Si7AlO22(OH)2 C 2/m 2/m

66.01.03c.11a Ferronyboite! NaNa2(Fe)3Al2(Si7Al)O22(OH)2 C 2/m 2/m

66.01.03c.11b Ferric-ferronyboite! NaNa2(Fe)3(Fe)2(Si7Al)O22(OH)2 C 2/m 2/m

66.01.03c.11c Fluoronyboite! NaNa2(Al2Mg3)(Si7Al)O22(F,OH)2 C 2/m 2/m

66.01.03c.12 Leakeite NaNa2(Mg2Fe2Li)Si8O22(OH)2 C 2/m 2/m

66.01.03c.12a Ferroleakeite! NaNa2(Fe)3(Fe)2Li(Si8O22)(OH)2 C 2/m 2/m

66.01.03c.12b Potassicleakeite! KNa2Mg2Fe2LiSi8O22(OH)2 C 2/m 2/m

66.01.03c.13 Kornite Na(CaNa)Fe4(Al,Fe)Si7AlO22(OH)2 C 2/m 2/m

66.01.03c.14 Ungarettiite NaNa2(Mn2Mn3)Si8O22O2 C 2/m 2/m

66.01.03c.15 Fluoro-ferroleakeite NaNa2(Fe2Fe2Li)Si8O22F2 C 2/m 2/m

66.01.03c.16 Obertiite! NaNa2(Mg3FeTi)Si8O22(O,F,OH)2 C 2/m 2/m

66.01.03c.17 Dellaventuraite! NaNa2(Mg2,Mn,Li,Ti)Si8O22O2 C 2/m 2/m

Strunz Class:

09.DE.25 09 - SILICATES (Germanates)

09.D - Inosilicates* Structural terminology according to Liebau (1985)

09.DE -Inosilicates with 2-periodic double chains, Si4O11; amphibole family

09.DE.25 Arfvedsonite NaNa2(Fe4Fe)Si8O22(OH)2 C 2/m 2/m

09.DE.25 Ferroglaucophane []Na2(Fe3Al2)Si8O22(OH)2 C 2/m 2/m

09.DE.25 Crossite? Na2(Mg,Fe)3(Al,Fe)2Si8O22(OH)2 C 2/m 2/m

09.DE.25 Eckermannite NaNa2(Mg4Al)Si8O22(OH)2 C 2/m 2/m

09.DE.25 Glaucophane []Na2(Mg3Al2)Si8O22(OH)2 C 2/m 2/m

09.DE.25 Fluoro-ferroleakeite NaNa2(Fe2Fe2Li)Si8O22F2 C 2/m 2/m

09.DE.25 Ferro-eckermannite NaNa2(Fe4Al)Si8O22(OH)2 C 2/m 2/m

09.DE.25 Ferroleakeite! NaNa2(Fe)3(Fe)2Li(Si8O22)(OH)2 C 2/m 2/m

09.DE.25 Ferronyboite! NaNa2(Fe)3Al2(Si7Al)O22(OH)2 C 2/m 2/m

09.DE.25 Ferric-ferronyboite! NaNa2(Fe)3(Fe)2(Si7Al)O22(OH)2 C 2/m 2/m

09.DE.25 Obertiite! NaNa2(Mg3FeTi)Si8O22(O,F,OH)2 C 2/m 2/m

09.DE.25 Nyboite NaNa2(Mg3Al2)Si7AlO22(OH)2 C 2/m 2/m

09.DE.25 Magnesioriebeckite []Na2[(Mg,Fe)3Fe2]Si8O22(OH)2 C 2/m 2/m

09.DE.25 Kozulite NaNa2Mn4(Fe,Al)Si8O22(OH)2 C 2/m 2/m

09.DE.25 Kornite Na(CaNa)Fe4(Al,Fe)Si7AlO22(OH)2 C 2/m 2/m

09.DE.25 Leakeite NaNa2(Mg2Fe2Li)Si8O22(OH)2 C 2/m 2/m

09.DE.25 Magnesio-arfvedsonite NaNa2(Mg4Fe)Si8O22(OH)2 C 2/m 2/m

09.DE.25 Ungarettiite NaNa2(Mn2Mn3)Si8O22O2 C 2/m 2/m

09.DE.25 Riebeckite []Na2(Fe3Fe2)Si8O22(OH)2 C 2/m 2/m

09.DE.25 Potassicleakeite! KNa2Mg2Fe2LiSi8O22(OH)2 C 2/m 2/m

09.DE.25 Fluoronyboite! NaNa2(Al2Mg3)(Si7Al)O22(F,OH)2 C 2/m 2/m

09.DE.25 Fluoro-magnesio-arfvedsonite! NaNa2(Mg,Fe)4Fe[Si8O22](F,OH)2 C 2/m 2/m

09.DE.25 Potassicarfvedsonite! KNa2Fe4FeSi8O22(OH)2 C 2/m 2/m

09.DE.25 Dellaventuraite! NaNa2(Mg2,Mn,Li,Ti)Si8O22O2 C 2/m 2/m

Other Magnesioriebeckite Information

References:

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

See Also:

Links to other databases for Magnesioriebeckite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - EUROmin Project
4 - Ecole des Mines de Paris
5 - Franklin Minerals(Dunn)
6 - GeoScienceWorld
7 - Google Images
8 - Google Scholar
9 - Handbook of Mineralogy (MinSocAm)
10 - Handbook of Mineralogy (UofA)
11 - MinDAT
12 - Mineralienatlas (Deutsch)
13 - Online Mineral Museum
14 - QUT Mineral Atlas
15 - Ruff.Info

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Magnesioriebeckite

[ ]Na2[(Mg,Fe++)3Fe+++2]Si8O22(OH)2
Dana No: 66.01.03c.04 Strunz No: 09.DE.25
Locality:

Notes:

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