Armbrusterite Mineral Data

General Armbrusterite Information

Chemical Formula:

K5Na6Mn+++Mn++14[Si9O22]4(OH)10•4H2O

Composition:

Molecular Weight = 3,806.38 gm

Potassium 5.17 % K 6.22 % K₂O

Sodium 3.96 % Na 5.33 % Na₂O

Calcium 0.19 % Ca 0.27 % CaO

Magnesium 0.11 % Mg 0.19 % MgO

Titanium 0.03 % Ti 0.04 % TiO₂

Manganese 20.02 % Mn 23.97 % MnO / 2.09 % Mn₂O₃

Aluminum 0.02 % Al 0.04 % Al₂O₃

Zinc 0.15 % Zn 0.19 % ZnO

Iron 0.51 % Fe 0.66 % FeO

Silicon 26.56 % Si 56.83 % SiO₂

Hydrogen 0.47 % H 4.16 % H₂O

Oxygen 42.81 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

K_5.03Na_6.55Mn²⁺_12.86Mn³⁺_1.01Fe²⁺_0.35Mg_0.18Ca_0.18Zn_0.09Al_0.03Ti_0.02Si₃₆O₈₈(OH)_10.1ï¿½3.75(H₂O)

Environment:

Modulated manganese phyllosilicate

IMA Status:

Approved IMA 2005 (Dana # Added)

Locality:

Mt. Kukisvumchorr, Kola Peninsula, Russia Link to MinDat.org Location Data.

Name Origin:

Named for Thomas Armbruster (b. 1950; University of Berne) for his outstanding contribution to structural mineralogy and crystallography, especially to the study of Mn-rich minerals .

Synonym:

IMA2005-035

Armbrusterite Image

Images:

Armbrusterite

Comments: SEM image of a spherulite of platy crystals of armbrusterite (2 mm diameter) on cancrinite and calcite. (AmMin, v92:416).
Location: Khibiny massif, Kola Peninsula, Russia.. Scale: Spherulite Size 2 mm.
© American Mineralogist

Images:

Armbrusterite

Comments: Translucent yellow-brown crystals of armbrusterite on small fragment of brown matrix.
Location: Kirovskii Mine, Mt. Kukisvumchorr, Khibiny, Kola Peninsula, Russia. Scale: Specimen Size 5x3x2 mm.
© John Betts - Fine Minerals

Armbrusterite Crystallography

Axial Ratios:

a:b:c =0.7363:1:0.573

Cell Dimensions:

a = 17.3335, b = 23.539, c = 13.4895, Z = 2; beta = 115.069° V = 4,985.42 Den(Calc)= 2.54

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): 12.28(1)(001 ), 3.077(0.54)(004 ), 3.26(0.18)(114 ),3.117(0.13)(203 ), 2.622(0.1)(371 ), 3.562(0.1)(113,261), 4.1(0.1)(003 ),

Physical Properties of Armbrusterite

Cleavage:

{001} Perfect

Color:

Dark reddish brown.

Density:

2.78

Diaphaneity:

Translucent to transparent

Fracture:

Brittle - Uneven - Very brittle fracture producing uneven fragments.

Habit:

Platy - Sheet forms (e.g. micas).

Habit:

Spherical - Spherical, rounded aggregates.

Hardness:

3.5 - Copper Penny

Luster:

Vitreous (Glassy)

Streak:

light brown

Optical Properties of Armbrusterite

Gladstone-Dale:

CI meas= 0.059 (Good) - where the CI = (1-KPDmeas/KC)
CI calc= -0.03 (Excellent) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2173,KPDmeas= 0.1986,KC= 0.2109
Ncalc = 1.54 - 1.59

Calculated Properties of Armbrusterite

Electron Density:

Bulk Density (Electron Density)=2.49 gm/cc
note: Specific Gravity of Armbrusterite =2.54 gm/cc.

Fermion Index:

Fermion Index = 0.01
Boson Index = 0.99

Photoelectric:

PE_{Armbrusterite}= 6.92 barns/electron
U=PE_{Armbrusterite} x r_electron= 17.26 barns/cc.

Radioactivity:

GRapi = 73.24 (Gamma Ray American Petroleum Institute Units)
Concentration of Armbrusterite per GRapi unit = 1.37 (%)

Estimated Radioactivity from Armbrusterite - barely detectable

Armbrusterite Classification

Dana Class:

74.01.03.02 (74)Phyllosilicate Modulated Layers

(74.01)with joined islands

(74.01.03)Dana Group

74.01.03.01 Parsettensite (K,Na,Ca)(Mn,Al)7Si8O20(OH)8•2(H2O)(?) C 2/m 2/m

74.01.03.02 Armbrusterite! K5Na6MnMn14[Si9O22]4(OH)10•4H2O C 2/m 2/m

Strunz Class:

09.EG.65 09 - SILICATES (Germanates)

09.E - Phyllosilicates

09.EG -Double nets with 6-membered and larger rings

09.EG.65 Armbrusterite! K5Na6MnMn14[Si9O22]4(OH)10•4H2O C 2/m 2/m

Other Armbrusterite Information

References:

NAME( AmMin, 92:416) PHYS. PROP.(AmMin, 92:416) OPTIC PROP.(AmMin, 92:416)

See Also:

Links to other databases for Armbrusterite :
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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Print or Cut-and-Paste your Armbrusterite Specimen Label here :

Armbrusterite

K5Na6Mn+++Mn++14[Si9O22]4(OH)10•4H2O
Dana No: 74.01.03.02 Strunz No: 09.EG.65
Locality:

Notes:

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