Simpsonite
A valid IMA mineral species - grandfathered
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About Simpsonite
Edward Sydney Simpson
Formula:
Al4Ta3O13(OH)
Colour:
Yellow, light brown or colourless, gray
Lustre:
Adamantine, Dull
Hardness:
7 - 7½
Specific Gravity:
6.35 (Calculated)
Crystal System:
Trigonal
Name:
Named in 1938 by Harry Bowley in honour of Edward Sydney Simpson (March 11, 1875, Woollahara, Western Australia, Australia - August 30, 1939, South Perth, Western Australia, Australia), government mineralogist and chemist of the Geological Survey of Western Australia. The Simpson Desert was also named for him.
Visit gemdat.org for Unique Identifiers
Mindat ID:
3670
Long-form identifier:
mindat:1:1:3670:8
Similar Names
| Impsonite | A variety of 'Pyrobitumen' |
IMA Classification of Simpsonite
Approved, 'Grandfathered' (first described prior to 1959)
IMA Formula:
Al4Ta5+3O13(OH)
First published:
1939
Classification of Simpsonite
4.DC.10
4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
D : Metal: Oxygen = 1:2 and similar
C : With medium-sized cations; sheets of edge-sharing octahedra
4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
D : Metal: Oxygen = 1:2 and similar
C : With medium-sized cations; sheets of edge-sharing octahedra
8.7.5.1
8 : MULTIPLE OXIDES CONTAINING NIOBIUM,TANTALUM OR TITANIUM
7 : Miscellaneous
8 : MULTIPLE OXIDES CONTAINING NIOBIUM,TANTALUM OR TITANIUM
7 : Miscellaneous
18.1.19
18 : Niobates and Tantalates
1 : Niobates and tantalates containing neither rare earths nor U
18 : Niobates and Tantalates
1 : Niobates and tantalates containing neither rare earths nor U
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 for Standard |
|---|---|---|
| Spn | 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 Simpsonite
Adamantine, Dull
Transparency:
Translucent
Colour:
Yellow, light brown or colourless, gray
Streak:
White
Hardness:
7 - 7½ on Mohs scale
Tenacity:
Brittle
Cleavage:
None Observed
Density:
6.35 g/cm3 (Calculated)
Optical Data of Simpsonite
Type:
Uniaxial (-)
RI values:
nω = 2.045 nε = 2.025
Max. Birefringence:
δ = 0.020
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.
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.
Surface Relief:
Moderate
Chemistry of Simpsonite
Mindat Formula:
Al4Ta3O13(OH)
Element Weights:
Elements listed:
Crystallography of Simpsonite
Crystal System:
Trigonal
Class (H-M):
3 - Pyramidal
Space Group:
P3
Cell Parameters:
a = 7.37 Å, c = 4.51 Å
Ratio:
a:c = 1 : 0.612
Unit Cell V:
212.15 ų (Calculated from Unit Cell)
Z:
1
Morphology:
Crystals tabular to short prismatic [0001].
Crystal Structure
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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) |
|---|---|---|---|---|---|---|---|
| 0005281 | Simpsonite | Ercit T S, Cerny P, Hawthorne F C (1992) The crystal chemistry of simpsonite The Canadian Mineralogist 30 663-671 |  | 1992 | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Loading XRD data...
Data courtesy of RRUFF project at University of Arizona, used with permission.
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 1.651 Å | (100) |
| 2.859 Å | (67) |
| 3.69 Å | (62) |
| 2.131 Å | (59) |
| 1.395 Å | (54) |
| 2.417 Å | (40) |
| 2.609 Å | (37) |
Comments:
Alto do Giz pegmatite, Brazil. Data are from Ercit et al. (1992).
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 4b: Highly evolved igneous rocks | >3.0 |
| 34 : Complex granite pegmatites |
Type Occurrence of Simpsonite
General Appearance of Type Material:
Poorly formed crystals approximating hexagonal prisms but showing only a few faces.
Place of Conservation of Type Material:
Western Australian Museum, Perth, numbers MDC1006, MDC1007.
The Natural History Museum, London, England, number 1938,122.
The Natural History Museum, London, England, number 1938,122.
Geological Setting of Type Material:
Primary mineral in Ta-rich granite pegmatites.
Synonyms of Simpsonite
Other Language Names for Simpsonite
Common Associates
Associations Based on Photo Data:
| 19 photos of Simpsonite associated with Tantalite-(Mn) | Mn2+Ta2O6 |
| 11 photos of Simpsonite associated with Alumotantite | AlTaO4 |
| 5 photos of Simpsonite associated with Rankamaite | (Na,K)3(Ta,Nb,Al)11(O,OH)31 |
| 4 photos of Simpsonite associated with Hydroxykenomicrolite | (◻,Na,Sb3+)2Ta2O6(OH,Cs) |
| 3 photos of Simpsonite associated with Cassiterite | SnO2 |
| 3 photos of Simpsonite associated with Tapiolite-(Fe) | Fe2+Ta2O6 |
| 3 photos of Simpsonite associated with Microlite Group | A2-mTa2X6-wZ1-n |
| 3 photos of Simpsonite associated with Titanowodginite | Mn2+TiTa2O8 |
| 2 photos of Simpsonite associated with Microcline | K(AlSi3O8) |
| 2 photos of Simpsonite associated with Tantalowodginite | (Mn2+0.5◻0.5)TaTa2O8 |
Related Minerals - Strunz-mindat Grouping
| 4.DC.05 | Bahianite | Al5Sb3O14(OH)2 |
Fluorescence of Simpsonite
May fluoresce blue-white, SW-UV.
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 Simpsonite
mindat.org URL:
https://www.mindat.org/min-3670.html
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Please feel free to link to this page.
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References for Simpsonite
Reference List:
KERR, PAUL F.; HOLMES, RALPH J. (1945) X-ray study of the tantalum mineral simpsonite. Geological Society of America Bulletin, 56 (5). p.479-504. doi:10.1130/0016-7606(1945)56[479:xsottm]2.0.co;2
McGregor, A. M. (1946) Simpsonite and other tantalates from Bikita, Southern Rhodesia. Mineralogical Magazine and Journal of the Mineralogical Society, 27 (192) 157-165 doi:10.1180/minmag.1946.027.192.03
von Knorring, O., Hornung, G. (1963) Simpsonite and stibiotantalite from Benson pegmatite mine, Mtoko, Southern Rhodesia. Mineralogical Magazine and Journal of the Mineralogical Society, 33 (261) 458-466 doi:10.1180/minmag.1963.033.261.03
Localities for Simpsonite
Showing 21 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.
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Alto do Giz pegmatite, Equador, Rio Grande do Norte, Brazil