Middendorfite
A valid IMA mineral species
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About Middendorfite
Alexander Theodor von Middendorff
Formula:
K3Na2Mn5Si12(O,OH)36 · 2H2O
Colour:
Dark to bright orange
Lustre:
Vitreous
Hardness:
3 - 3½
Specific Gravity:
2.60
Crystal System:
Monoclinic
Name:
For Aleksandr Fedorovich von Middendorf (18 August 1815 – 24 January 1894), a German-Russian scientist who made the first mineralogical studies on the Khibiny massif.
Unique Identifiers
Mindat ID:
28996
Long-form identifier:
mindat:1:1:28996:8
GUID
(UUID V4):
(UUID V4):
358c864f-3b30-4dc8-b7a4-b8f712727828
Classification of Middendorfite
Approved
Approval year:
2005
First published:
2006
Type description reference:
9.EJ.10
9 : SILICATES (Germanates)
E : Phyllosilicates
J : Unclassified phyllosilicates
9 : SILICATES (Germanates)
E : Phyllosilicates
J : Unclassified phyllosilicates
Mineral Symbols
As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
| Symbol | Source | Reference |
|---|---|---|
| Mdd | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
Physical Properties of Middendorfite
Vitreous
Transparency:
Transparent
Colour:
Dark to bright orange
Streak:
yellowish
Hardness:
3 - 3½ on Mohs scale
Tenacity:
Flexible
Cleavage:
Perfect
on (001)
on (001)
Fracture:
Sub-Conchoidal
Comment:
fracture scaly
Density:
2.60 g/cm3 (Measured) 2.65 g/cm3 (Calculated)
Optical Data of Middendorfite
Type:
Biaxial (-)
RI values:
nα = 1.534(3) nβ = 1.562(2) nγ = 1.563(2)
2V:
Measured: 10° (5), Calculated: 21°
Max Birefringence:
δ = 0.029
Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.
and does not take into account mineral colouration.
Surface Relief:
Low
Pleochroism:
Strong
Comments:
X = yellowish to colorless; Y = brown;
Z = deep brown
Z = deep brown
Chemical Properties of Middendorfite
Formula:
K3Na2Mn5Si12(O,OH)36 · 2H2O
Crystallography of Middendorfite
Crystal System:
Monoclinic
Cell Parameters:
a = 12.55(1) Å, b = 5.721(2) Å, c = 26.86(2) Å
β = 114.04(7)°
β = 114.04(7)°
Ratio:
a:b:c = 2.194 : 1 : 4.695
Unit Cell V:
1761 ų
Z:
2
Comment:
Point Group: 2/m or 2; Space Group: P21/m or P21.
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 12.28 Å | (100) |
| 2.840 Å | (90) |
| 2.634 Å | (88) |
| 4.31 Å | (81) |
| 2.366 Å | (76) |
| 1.669 Å | (64) |
| 3.555 Å | (62) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 4b: Highly evolved igneous rocks | >3.0 |
| 35 : Ultra-alkali and agpaitic igneous rocks |
Type Occurrence of Middendorfite
General Appearance of Type Material:
Coarse, rhomb-like lamellar and tabular crystals up to 0.1 x 0.2 x 0.4 mm in size, combined in worm- and fan-like aggregates up to 1 mm
Place of Conservation of Type Material:
A.E. Fersman Mineralogical Museum, Russian Academy of Sciences, Moscow, 3312/1.
Geological Setting of Type Material:
late hydrothermal mineral in a hyperperalkaline pegmatite
Associated Minerals at Type Locality:
Reference:
Pekov, I.V., Chukanov, N.V., Dubinchuk, V.T., Zadov, A.E. (2006) Middendorfite, K3Na2Mn5Si12(O,OH)36• 2H2O, a new mineral from Khibiny Massif, Kola Peninsula. Proceedings of the Russian Mineralogical Society: 135(3): 42–52.
Synonyms of Middendorfite
Related Minerals - Strunz-mindat Grouping
| 9.EJ.05 | Lourenswalsite | (K,Ba)2(Ti,Mg,Ca,Fe)4(Si,Al,Fe)6O14(OH)12 | Hex. |
| 9.EJ.15 | Lipuite | KNa8Mn3+5 Mg0.5[Si12O30(OH)4](PO4)O2(OH)2 · 4H2O | Orth. mmm (2/m 2/m 2/m) : Pnnm |
| 9.EJ.20 | Odigitriaite | CsNa5Ca5[Si14B2O38]F2 | Mon. 2/m : B2/b |
Other Information
Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.
Internet Links for Middendorfite
mindat.org URL:
https://www.mindat.org/min-28996.html
Please feel free to link to this page.
Please feel free to link to this page.
External Links:
Mineral Dealers:
References for Middendorfite
Reference List:
Localities for Middendorfite
symbol to view information about a locality.
The Locality List
- This locality has map coordinates listed.
- This locality has estimated coordinates.
ⓘ - Click for references and further information on this occurrence.
? - Indicates mineral may be doubtful at this locality.
- Good crystals or important locality for species.
- World class for species or very significant.
(TL) - Type Locality for a valid mineral species.
(FRL) - First Recorded Locality for everything else (eg varieties).
All localities listed without proper references should be considered as questionable.
Russia (TL) | |
|
Hilairitovoye pegmatite, Kirovskii apatite mine, Kukisvumchorr Mt, Khibiny Massif, Murmansk Oblast, Russia