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Rogermitchellite
A valid IMA mineral species
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Formula:
Na6Sr12Ba2Zr13Si39B4O123(OH)6 · 20H2O
Colour:
Colourless to grey
Lustre:
Vitreous
Hardness:
5
Specific Gravity:
3.34 (Calculated)
Crystal System:
Hexagonal
Name:
Named after Dr. Roger Howard Mitchell (b. 1941), Professor Emeritus in the Departement of Geology at Lakehead University, Thunder Bay, Ontario, Canada in recognition of his outstanding contributions to the mineralogy and petrology of alkaline rocks.
Unique Identifiers
Mindat ID:
27514
Long-form identifier:
mindat:1:1:27514:1
IMA Classification of Rogermitchellite
Approved
IMA Formula:
Na6Sr12Ba2Zr4+13Si39B6O123(OH)14·10H2O
Approval year:
2003
First published:
2010
Classification of Rogermitchellite
9.CA.35
9 : SILICATES (Germanates)
C : Cyclosilicates
A : [Si3O9]6- 3-membered single rings (dreier-Einfachringe), without insular complex anions
9 : SILICATES (Germanates)
C : Cyclosilicates
A : [Si3O9]6- 3-membered single rings (dreier-Einfachringe), without insular complex anions
Mineral Symbols
As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
Please only use the official IMA–CNMNC symbol. Older variants are listed for historical use only.
Please only use the official IMA–CNMNC symbol. Older variants are listed for historical use only.
| Symbol | Source | Reference for Standard |
|---|---|---|
| Rmt | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
| Whitney & Evans (2010) | Whitney, D.L. and Evans, B.W. (2010) Abbreviations for names of rock-forming minerals. American Mineralogist, 95, 185–187 doi:10.2138/am.2010.3371 |
Physical Properties of Rogermitchellite
Vitreous
Transparency:
Transparent
Colour:
Colourless to grey
Streak:
White
Hardness:
5 on Mohs scale
Tenacity:
Very brittle
Cleavage:
None Observed
Fracture:
Splintery, Conchoidal
Density:
3.34(1) g/cm3 (Calculated)
Comment:
Calculated value based on the empirical formula.
Optical Data of Rogermitchellite
Type:
Uniaxial (+)
RI values:
nω = 1.64 nε = 1.663
Max. Birefringence:
δ = 0.023
Based on recorded range of RI values above.
Based on recorded range of RI values above.
Interference Colours:
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.
Surface Relief:
High (positive)
Relative to Canada balsam mounting medium (n ≈ 1.537).
Relative to Canada balsam mounting medium (n ≈ 1.537).
This shows the grain boundary and Becke line effect under plane-polarised
light, based on the contrast between this mineral's average refractive
index and the mounting medium. It does not take into account mineral
colouration.
In focus
Interference Figure:
This shows the idealized uniaxial interference figure - the conoscopic
(convergent-light, Bertrand-lens-in) view, for a grain cut with the optic axis
centred and vertical. The coloured rings are isochromatics, computed with the
same physics as the Michel-Lévy bar above; the dark cross is the isogyre.
For a genuinely uniaxial mineral viewed this way, that cross stays perfectly stationary if you rotate the stage - unlike a biaxial mineral, where it splits apart on rotation. That invariance is itself the standard diagnostic test for telling uniaxial and biaxial minerals apart at the microscope.
For a genuinely uniaxial mineral viewed this way, that cross stays perfectly stationary if you rotate the stage - unlike a biaxial mineral, where it splits apart on rotation. That invariance is itself the standard diagnostic test for telling uniaxial and biaxial minerals apart at the microscope.
Chemistry of Rogermitchellite
Mindat Formula:
Na6Sr12Ba2Zr13Si39B4O123(OH)6 · 20H2O
Element Weights:
Crystallography of Rogermitchellite
Crystal System:
Hexagonal
Class (H-M):
6mm - Dihexagonal Pyramidal
Space Group:
P63cm
Cell Parameters:
a = 26.509 Å, c = 9.975 Å
Ratio:
a:c = 1 : 0.376
Unit Cell V:
6,070.58 ų (Calculated from Unit Cell)
Morphology:
Type material:
Prismatic along [001], and slightly flattened perpendicular to this direction. Prominent forms include the prism {100} and pinacoid {001}, with a minor, very shallow ditrigonal scalenohedron {10l}.
Prismatic along [001], and slightly flattened perpendicular to this direction. Prominent forms include the prism {100} and pinacoid {001}, with a minor, very shallow ditrigonal scalenohedron {10l}.
Crystal Structure
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Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
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Data courtesy of the American Mineralogist Crystal Structure Database. Click on an AMCSD ID to view structure
| ID | Species | Reference | Link | Year | Locality | Pressure (GPa) | Temp (K) |
|---|---|---|---|---|---|---|---|
| 0006329 | Rogermitchellite | McDonald A M, Chao G Y (2010) Rogermitchellite, Na12(Sr,Na)24Ba4Zr26Si78(B,Si)12O246(OH)24?18H2O, a new mineral species from Mont Saint-Hilaire, Quebec: Description, structure determination and relationship with HFSE-bearing cyclosilicates The Canadian Mineralogist 48 267-278 | 2010 | Mont Saint-Hilaire, Quebec, Canada | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 5.76 Å | (40) |
| 3.924 Å | (30) |
| 3.761 Å | (90) |
| 3.310 Å | (25) |
| 3.150 Å | (50) |
| 2.760 Å | (100) |
| 1.991 Å | (70) |
Comments:
From type description.
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 Rogermitchellite
General Appearance of Type Material:
Free-standing crystals in vugs. Isolated, single crystals are prismatic slightly flattened perpendicular to the elongation, with a maximum dimension of 0.1 x 3 x 0.25 mm.
Place of Conservation of Type Material:
Canadian Museum of Nature, Ottawa, Ontario, Canada, CMNMC 860087.
Geological Setting of Type Material:
A late-stage igneous breccia in nepheline syenite.
Associated Minerals at Type Locality:
Synonyms of Rogermitchellite
Other Language Names for Rogermitchellite
Dutch:Rogermitchelliet
German:Rogermitchellit
Related Minerals - Strunz-mindat Grouping
| 9.CA. | 'UM1975-18-SiO:Mn' | α-MnSiO3 |
| 9.CA. | Raudseppite | Ba2Ca7(Si3O9)2(CO3)2Cl2 |
| 9.CA. | Kopylovite | K2Ti(Si3O9) |
| 9.CA.05 | Bazirite | BaZr(Si3O9) |
| 9.CA.05 | Benitoite | BaTi(Si3O9) |
| 9.CA.05 | Pabstite | Ba(Sn,Ti)(Si3O9) |
| 9.CA.10 | Wadeite | K2Zr(Si3O9) |
| 9.CA.15 | Calciocatapleiite | CaZr(Si3O9) · 2H2O |
| 9.CA.15 | Catapleiite | Na2Zr(Si3O9) · 2H2O |
| 9.CA.20 | Pseudowollastonite | CaSiO3 |
| 9.CA.25 | Margarosanite | Ca2PbSi3O9 |
| 9.CA.25 | Walstromite | BaCa2(Si3O9) |
| 9.CA.25 | Anatolygurbanovite | SrCa2Si3O9 |
| 9.CA.25 | Breyite | Ca3Si3O9 |
| 9.CA.30 | Bobtraillite | (Na,◻)12(◻,Na)12Sr12Zr14(Si3O9)10[Si2BO7(OH)2]6 · 12H2O |
Fluorescence of Rogermitchellite
Not fluorescent.
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 Rogermitchellite
mindat.org URL:
https://www.mindat.org/min-27514.html
Please feel free to link to this page.
Please feel free to link to this page.
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References for Rogermitchellite
Reference List:
McDonald, Andrew M., Chao, George Y. (2010) Rogermitchellite, Na12(Sr,Na)24Ba4Zr26Si78(B,Si)12O246(OH)24 · 18H2O, a new mineral species from Mont Saint-Hilaire, Quebec: description, structure determination and relationship with HFSE-bearing cyclosilicates. The Canadian Mineralogist, 48 (2) 267-278 doi:10.3749/canmin.48.2.267
Localities for Rogermitchellite
Showing 1 localities.
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.
Canada (TL) | |
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