Middendorfite Mineral Data

General Middendorfite Information

Chemical Formula:

K3Na2Mn5Si12(O,OH)36•2H2O

Composition:

Molecular Weight = 1,408.07 gm

Potassium 8.44 % K 10.17 % K₂O

Sodium 3.38 % Na 4.56 % Na₂O

Calcium 0.09 % Ca 0.12 % CaO

Magnesium 0.10 % Mg 0.17 % MgO

Titanium 0.10 % Ti 0.17 % TiO₂

Manganese 19.31 % Mn 24.94 % MnO

Aluminum 0.11 % Al 0.22 % Al₂O₃

Zinc 0.14 % Zn 0.17 % ZnO

Iron 0.52 % Fe 0.66 % FeO

Silicon 23.82 % Si 50.95 % SiO₂

Hydrogen 0.87 % H 7.74 % H₂O

Oxygen 42.89 % O

Fluorine 0.23 % F 0.23 % F

- % F -0.10 % -O=F₂

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

K_3.04Na_2.07Ca_0.03Mn²⁺_4.95Fe²⁺_0.13Mg_0.06Ti_0.03Zn_0.03Si_11.94Al_0.06O_27.57(OH)_8.26F_0.17ï¿½1.92(H₂O)

Environment:

Found in a hydrothermal assemblage in Hilairite hyperperalkaline pegmatite. Related to ganophyllite- and stilpnomelane-group minerals

IMA Status:

Approved IMA 2005 (Dana # Added)

Locality:

Kirovskii apatite mine, Kukisvumchorr, Khibiny alkaline massif, Kola Peninsula, Russia. Link to MinDat.org Location Data.

Name Origin:

Named for A.F. von Middendorff (1815-1894), an outstanding scientist, who carried out the first mineralogical investigations in the Khibiny pluton.

Synonym:

IMA2005-028

Middendorfite Image

Images:

Middendorfite

Comments: Dark orange platy middendorfite in quartz matrix.
Location: Kirovskii Mine, Kukisvumchorr, Chibiny, Kola, Russia. Scale: Not Given.
© Diederik Visser

Middendorfite Crystallography

Axial Ratios:

a:b:c =2.1936:1:4.6949

Cell Dimensions:

a = 12.55, b = 5.721, c = 26.86, Z = 2; beta = 114.04° V = 1,761.23 Den(Calc)= 2.65

Crystal System:

Monoclinic Space Group: P 2₁/m or P 2₁

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

By Intensity(I/I_o): 12.28(1), 2.84(0.9), 2.634(0.88),4.31(0.81), 2.366(0.76), 1.669(0.64), 3.555(0.62), 1.614(0.56),

Physical Properties of Middendorfite

Cleavage:

{001} Perfect

Color:

Dark orange.

Density:

2.6

Diaphaneity:

Transparent

Fracture:

Micaceous - Fracture of flexable micaceous cleavage fragments.

Habit:

Lamellar - Thin laminae producing a lamellar structure.

Habit:

Radial - Crystals radiate from a center without producing stellar forms (e.g. stibnite)

Habit:

Tabular - Form dimensions are thin in one direction.

Hardness:

3-3.5 - Calcite-Copper Penny

Luster:

Vitreous (Glassy)

Streak:

pale yellow

Optical Properties of Middendorfite

Gladstone-Dale:

CI meas= 0.003 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= 0.022 (Excellent) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2087,KPDmeas= 0.2127,KC= 0.2133
Ncalc = 1.55 - 1.57

Optical Data:

Biaxial (-), a=1.534, b=1.562, g=1.563, bire=0.0290

Calculated Properties of Middendorfite

Electron Density:

Bulk Density (Electron Density)=2.56 gm/cc
note: Specific Gravity of Middendorfite =2.60 gm/cc.

Fermion Index:

Fermion Index = 0.01
Boson Index = 0.99

Photoelectric:

PE_{Middendorfite}= 6.94 barns/electron
U=PE_{Middendorfite} x r_electron= 17.78 barns/cc.

Radioactivity:

GRapi = 120.09 (Gamma Ray American Petroleum Institute Units)
Concentration of Middendorfite per GRapi unit = 0.83 (%)

Estimated Radioactivity from Middendorfite - barely detectable

Middendorfite Classification

Dana Class:

74.01.01.05 (74)Phyllosilicate Modulated Layers

(74.01)with joined islands

(74.01.01)Stilpnomelane group

74.01.01.01 Stilpnomelane K(Fe,Mg,Fe)8(Si,Al)12(O,OH)27•n(H2O) P1 1

74.01.01.02 Lennilenapeite K6-7(Mg,Mn,Fe,Fe,Zn)48(Si,Al)72(O,OH)216•16(H2O) Unk (pseudo-HEX) Tri

74.01.01.03 Franklinphilite (K,Na)4(Mn,Mg,Zn)48(Si,Al)72(O,OH)216•6(H2O) pseudo-HEX P1 or P1 Tri

74.01.01.04 Bannisterite KCa(Mn,Fe,Zn,Mg)21(Si,Al)32O76(OH)16•4-12(H2O) A2/a 2/m

74.01.01.05 Middendorfite! K3Na2Mn5Si12(O,OH)36•2H2O P 2₁/m or P 2₁ Mono

Strunz Class:

09.EJ.10 09 - SILICATES (Germanates)

09.E - Phyllosilicates

09.EJ -Unclassified phyllosilicates

09.EJ.10 Middendorfite! K3Na2Mn5Si12(O,OH)36•2H2O P 2₁/m or P 2₁ Mono

Other Middendorfite Information

References:

NAME( Geology of Ore Deposits, v49:522) PHYS. PROP.(Geology of Ore Deposits, v49:522) OPTIC PROP.(Geology of Ore Deposits, v49:522)

See Also:

Links to other databases for Middendorfite :
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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Middendorfite

K3Na2Mn5Si12(O,OH)36•2H2O
Dana No: 74.01.01.05 Strunz No: 09.EJ.10
Locality:

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