Tancoite
A valid IMA mineral species
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About Tancoite
Formula:
LiNa2Al(PO4)(PO3OH)(OH)
Colour:
Colorless to light pink
Lustre:
Vitreous, Sub-Vitreous
Hardness:
4 - 4½
Specific Gravity:
2.752
Crystal System:
Orthorhombic
Name:
Named in 1980 by Robert A. Ramik, Bozidar Darko Sturman, Pete J. Dunn, and Alexander Sergevich Povarennykh for its discovery locality, the Tanco Mine (pegmatite), Bernic Lake, Manitoba, Canada.
Colorless to pale pink tabular crystals
Unique Identifiers
Mindat ID:
3879
Long-form identifier:
mindat:1:1:3879:5
Similar Names
| Tancaite-(Ce) | A valid IMA mineral species | FeCe(MoO4)3 · 3H2O |
| Tanguéite | A synonym of Tangeite | |
| Tankite (of Haidinger) | A synonym of Xenotime-(Y) |
IMA Classification of Tancoite
Approved
Approval year:
1979
First published:
1980
Classification of Tancoite
8.BG.15
8 : PHOSPHATES, ARSENATES, VANADATES
B : Phosphates, etc., with additional anions, without H2O
G : With medium-sized and large cations, (OH, etc.):RO4 = 0.5:1
8 : PHOSPHATES, ARSENATES, VANADATES
B : Phosphates, etc., with additional anions, without H2O
G : With medium-sized and large cations, (OH, etc.):RO4 = 0.5:1
41.4.7.1
41 : ANHYDROUS PHOSPHATES, ETC.CONTAINING HYDROXYL OR HALOGEN
4 : (AB)5(XO4)2Zq
41 : ANHYDROUS PHOSPHATES, ETC.CONTAINING HYDROXYL OR HALOGEN
4 : (AB)5(XO4)2Zq
19.8.4
19 : Phosphates
8 : Phosphates of Al and other metals
19 : Phosphates
8 : Phosphates of Al and other metals
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 |
|---|---|---|
| Tco | 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 Tancoite
Vitreous, Sub-Vitreous
Transparency:
Transparent
Colour:
Colorless to light pink
Streak:
White
Hardness:
4 - 4½ on Mohs scale
Tenacity:
Brittle
Cleavage:
Imperfect/Fair
{010} and {100}
{010} and {100}
Fracture:
Conchoidal, Sub-Conchoidal
Density:
2.752 g/cm3 (Measured) 2.724 g/cm3 (Calculated)
Optical Data of Tancoite
Type:
Biaxial (-)
RI values:
nα = 1.541 nβ = 1.563 nγ = 1.564
2V:
Measured: 23° , Calculated: 24°
Birefringence:
0.023
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:
Low (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 biaxial acute bisectrix (Bxa) interference figure
- the conoscopic view for a grain cut perpendicular to the acute bisectrix, using
this mineral's 2V. The two small white dots mark the melatopes - the points
where the two optic axes emerge - and are shown only when they fall within the
field of view. The coloured bands are isochromatics, and the dark bands are
isogyres.
Rotate the stage: at 0°/90° the isogyres form a cross through the melatopes; at 45° they pull apart into curved hyperbolas. That splitting on rotation - absent in a uniaxial figure - is the standard diagnostic test for telling biaxial minerals from uniaxial ones. If 2V is large, the melatopes may fall outside the field of view, as they often do at the microscope too.
Rotate the stage: at 0°/90° the isogyres form a cross through the melatopes; at 45° they pull apart into curved hyperbolas. That splitting on rotation - absent in a uniaxial figure - is the standard diagnostic test for telling biaxial minerals from uniaxial ones. If 2V is large, the melatopes may fall outside the field of view, as they often do at the microscope too.
Dispersion:
r
Optical Extinction:
XYZ = cba
Pleochroism:
Non-pleochroic
Chemistry of Tancoite
Mindat Formula:
LiNa2Al(PO4)(PO3OH)(OH)
Element Weights:
Crystallography of Tancoite
Crystal System:
Orthorhombic
Class (H-M):
mmm(2/m2/m2/m) - Dipyramidal
Space Group:
Pbca
Cell Parameters:
a = 14.08 Å, b = 14.13 Å, c = 6.97 Å
Ratio:
a:b:c = 0.996 : 1 : 0.493
Unit Cell V:
1,386.68 ų (Calculated from Unit Cell)
Z:
8
Comment:
Pbcb
Crystal Structure
Load
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
Show
Big Balls | Small Balls | Just Balls | Spacefill
Polyhedra Off | Si Polyhedra | All Polyhedra
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Big Balls | Small Balls | Just Balls | Spacefill
Polyhedra Off | Si Polyhedra | All Polyhedra
Remove metal-metal sticks
Display Options
Black Background | White Background
Perspective On | Perspective Off
2D | Stereo | Red-Blue | Red-Cyan
Black Background | White Background
Perspective On | Perspective Off
2D | Stereo | Red-Blue | Red-Cyan
View
CIF File Best | x | y | z | a | b | c
CIF File Best | x | y | z | a | b | c
Rotation
Stop | Start
Stop | Start
Labels
Console Off | On | Grey | Yellow
Console Off | On | Grey | Yellow
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) |
|---|---|---|---|---|---|---|---|
| 0015695 | Tancoite | Hawthorne F C (1983) The crystal structure of tancoite Tschermaks Mineralogische und Petrographische Mitteilungen 31 121-135 | 1983 | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 4.672 Å | (100) |
| 3.413 Å | (90) |
| 3.150 Å | (100) |
| 2.479 Å | (90) |
| 1.760 Å | (40) |
| 1.438 Å | (40) |
| 1.429 Å | (40) |
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 Tancoite
General Appearance of Type Material:
Isolated crystals up to 1 mm in length and as druses of columnar individuals, oriented subparallel to [001].
Place of Conservation of Type Material:
Harvard Mineralogical Museum, Cambridge, Massachusetts, USA, number 117129 (cotype).
University of Manitoba, Winnipeg, Manitoba, Canada, number M5553/4 (cotype).
Natural History Museum, London, United Kingdom, number BM 1980,52 (cotype).
National Museum of Natural History, Washington, D.C., USA, number 146248 (type).
Royal Ontario Museum, Toronto, Ontario, Canada, number M36416-M34418 (cotype).
University of Manitoba, Winnipeg, Manitoba, Canada, number M5553/4 (cotype).
Natural History Museum, London, United Kingdom, number BM 1980,52 (cotype).
National Museum of Natural History, Washington, D.C., USA, number 146248 (type).
Royal Ontario Museum, Toronto, Ontario, Canada, number M36416-M34418 (cotype).
Geological Setting of Type Material:
LCA granite pegmatite.
Associated Minerals at Type Locality:
Synonyms of Tancoite
Other Language Names for Tancoite
Common Associates
Associations Based on Photo Data:
| 1 photo of Tancoite associated with Lithiophosphate | Li3PO4 |
| 1 photo of Tancoite associated with 'Apatite' | Ca5(PO4)3A |
Related Minerals - Strunz-mindat Grouping
| 8.BG. | Aldomarinoite | Sr2Mn3+(AsO4)2(OH) |
| 8.BG. | Dongchuanite | Pb4ZnZn2(PO4)4(OH)2 |
| 8.BG. | Cuprodongchuanite | Pb4CuZn2(PO4)4(OH)2 |
| 8.BG. | Canosioite | Ba2Fe3+(AsO4)2(OH) |
| 8.BG.05 | Feinglosite | Pb2Zn(AsO4)2 · H2O |
| 8.BG.05 | Tokyoite | Ba2Mn3+(VO4)2(OH) |
| 8.BG.05 | Lombardoite | Ba2Mn3+(AsO4)2(OH) |
| 8.BG.05 | Bearthite | Ca2Al(PO4)2(OH) |
| 8.BG.05 | 'Unnamed (possible ordered As-analogue of Tokyoite)' | Ba2Mn[(As,V)O4]2(OH) |
| 8.BG.05 | Gamagarite | Ba2Fe3+(VO4)2(OH) |
| 8.BG.05 | Arsentsumebite | Pb2Cu(AsO4)(SO4)(OH) |
| 8.BG.05 | 'UM1994-19-PO:CuHMoPb' | Pb2Cu(PO4)(MoO4,AsO4,CrO4,GaO4)(OH) |
| 8.BG.05 | Ferribushmakinite | Pb2Fe3+(PO4)(VO4)(OH) |
| 8.BG.05 | Arsenbrackebuschite | Pb2Fe3+(AsO4)2(OH) |
| 8.BG.05 | Goedkenite | Sr2Al(PO4)2(OH) |
| 8.BG.05 | Tsumebite | Pb2Cu(PO4)(SO4)(OH) |
| 8.BG.05 | Brackebuschite | Pb2Mn3+(VO4)2(OH) |
| 8.BG.05 | Bushmakinite | Pb2Al(PO4)(VO4)(OH) |
| 8.BG.05 | Calderónite | Pb2Fe3+(VO4)2(OH) |
| 8.BG.10 | Mélonjosephite | CaFe2+Fe3+(PO4)2(OH) |
| 8.BG.20 | Dmisokolovite | K3Cu5AlO2(AsO4)4 |
| 8.BG.25 | Shchurovskyite | K2CaCu6O2(AsO4)4 |
| 8.BG.30 | Wrightite | K2Al2O(AsO4)2 |
| 8.BG.35 | Polyarsite | Na7CaMgCu2(AsO4)4F2Cl |
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 Tancoite
mindat.org URL:
https://www.mindat.org/min-3879.html
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Please feel free to link to this page.
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References for Tancoite
Reference List:
Ramik, R. A., Sturman, B. D., Dunn, P. J., Povarennykh, A. S. (1980) Tancoite, a new lithium sodium aluminum phosphate from the Tanco pegmatite, Bernic Lake, Manitoba. The Canadian Mineralogist, 18 (2) 185-190
Localities for Tancoite
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) | |
| 153-155. +4 other references |
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Tanco Mine, Bernic Lake, Lac-du-Bonnet area, Manitoba, Canada