Strontiomelane Mineral Data

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General Strontiomelane Information

Chemical Formula:

SrMn++++6Mn+++2O16

Composition:

Molecular Weight = 783.11 gm

Strontium 11.19 % Sr 13.23 % SrO

Manganese 56.12 % Mn 20.16 % Mn₂O₃ / 66.61 % MnO₂

Oxygen 32.69 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

SrMn⁴⁺₆Mn³⁺₂O₁₆

Environment:

Post-Alpine stage of veining. Sr end-member of the cryptomelane group.

IMA Status:

Approved IMA 1999 (Dana # Added)

Locality:

Found at the Praborna manganese mine, near Saint-Marcel, Aosta Valley, Italian Alps. Link to MinDat.org Location Data.

Name Origin:

The name reflects the presence of strontium and the black color, melanos in Greek.

Synonym:

IMA1995-005

Strontiomelane Image

Images:

Strontiomelane

Comments: BSE image of strontiomelane. (CanMin, v37:673).
Location: Praboma mine near Saint-Marcel, Aosta Valley, Italian Alps, Italy. Scale: Scale Bar 100 µm.
© Canadian Mineralogist

Strontiomelane Crystallography

Axial Ratios:

a:b:c =1.7367:1:1.7158

Cell Dimensions:

a = 10, b = 5.758, c = 9.88, Z = 2; beta = 90.64° V = 568.85 Den(Calc)= 4.57

Crystal System:

Monoclinic - PrismaticH-M Symbol (2/m) Space Group: P 2₁/m

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

By Intensity(I/I_o): 3.15(1)(103), 3.13(0.8)(103), 2.409(0.8)(122),2.17(0.6)(320), 1.556(0.5)(225),

Physical Properties of Strontiomelane

Cleavage:

{???} Distinct

Color:

Black.

Diaphaneity:

Opaque

Fracture:

Brittle - Generally displayed by glasses and most non-metallic minerals.

Habit:

Anhedral Grains - Granular minerals without the expression of crystal shapes

Habit:

Inclusions - Generally found as inclusions in other minerals.

Habit:

Microscopic Crystals - Crystals visible only with microscopes.

Hardness:

4-4.5 - Between Fluorite and Apatite

Luster:

Sub Metallic

Streak:

sepia brown

Optical Properties of Strontiomelane

Optical Data:

NCalc= 2.56 - from Gladstone-Dale relationship (KC = 0.3423) where Ncalc=Dcalc*KC+1

RL Anisotrophism:

Moderate, from gray-blue to white.

RL Color:

Gray color in oil.

RL Pleochroism:

Strong gray-white in oil.

Reflectivity

**Standardized Intensity (100%) Reflection Spectra of Strontiomelane in Air**
λ	R₁	R₂	∑ R₁(λ)	∑ R₂(λ)
470 nm	34.20	26.00
543 nm	31.70	24.40
587 nm	30.60	23.40
657 nm	29.70	22.30

**Calculated Relative Intensity Colors of Strontiomelane in Air**
Relative Intensity	0%	40%	80%	100%	120%	160%	200%	240%	280%	320%	360%	380%
R₁
R₂

Calculated Properties of Strontiomelane

Electron Density:

Bulk Density (Electron Density)=4.27 gm/cc
note: Specific Gravity of Strontiomelane =4.57 gm/cc.

Fermion Index:

Fermion Index = 0.0079889633
Boson Index = 0.9920110367

Photoelectric:

PE_{Strontiomelane}= 27.51 barns/electron
U=PE_{Strontiomelane} x rElectron Density= 117.53 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Strontiomelane is Not Radioactive

Strontiomelane Classification

Dana Class:

07.09.01.05 (07)Multiple Oxides

(07.09)Dana Type

(07.09.01)Cryptomelane Group (Hard black, fine-grained)

07.09.01.01 Hollandite Ba(Mn,Mn)8O16 I2/m 2/m

07.09.01.02 Cryptomelane K(Mn,Mn)8O16 I2/m 2/m

07.09.01.03 Manjiroite (Na,K)(Mn,Mn)8O16•n(H2O) I 4/m 4/m

07.09.01.04 Coronadite Pb(Mn,Mn)8O16 I2/m 2/m

07.09.01.05 Strontiomelane! SrMn6Mn2O16 P 2₁/m 2/m

07.09.01.06 Henrymeyerite! BaFeTi7O16 I 4/m 4/m

Strunz Class:

04.DK.10 04 - OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodate

04.D - Metal:Oxygen = 1:2 and similar

04.DK -With large (± medium-sized) cations; tunnel structures

04.DK.10 Cryptomelane K(Mn,Mn)8O16 I2/m 2/m

04.DK.10 Todorokite (Na,Ca,K)2(Mn,Mn)6O12•3-4.5(H2O) P 2/m 2/m

04.DK.10 Romanechite (Ba,H2O)2(Mn,Mn)5O10 C 2/m 2/m

04.DK.10 Strontiomelane! SrMn6Mn2O16 P 2₁/m 2/m

Other Strontiomelane Information

References:

NAME( CanMin, 8/99) PHYS. PROP.(AmMin, V 85, p628) OPTIC PROP.(AmMin, V 85, p628)

See Also:

Links to other databases for Strontiomelane :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - GeoScienceWorld
4 - Google Images
5 - Google Scholar
6 - Handbook of Mineralogy (MinSocAm)
7 - Handbook of Mineralogy (UofA)
8 - MinDAT
9 - Mineralienatlas (Deutsch)
10 - Online Mineral Museum
11 - QUT Mineral Atlas
12 - Ruff.Info

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

Strontiomelane

SrMn++++6Mn+++2O16
Dana No: 07.09.01.05 Strunz No: 04.DK.10
Locality:

Notes: