Elliottite
A valid IMA mineral species
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About Elliottite
Peter Elliott and John Toma
Formula:
NaMgAl3(PO4)2F6 · 9H2O
Colour:
Colorless. White in aggregates.
Specific Gravity:
2.09 (Calculated)
Crystal System:
Monoclinic
Name:
The name is for Peter Elliott (born 1954) in recognition of his significant contributions to the characterization and naming of more than 30 new minerals from Australian localities (half of which he personally collected) and in particular his major contributions to the descriptions of new phosphate minerals from South Australian deposits. These include airdite, bimbowrieite, penriceite, plumboperloffite, puttapaite, reaphookhillite, whiteite-(MnMnMg) and whiterockite. He is also first author on a review of the phosphate deposits of South Australia (Elliott et al., 2013).
Dimorph of:
Closely related, both compositionally and structurally, to tomsquarryite (OH-dominant).
Represents a new type of crandallite-derivative layered structure. Topology of Al-centred corner-sharing octahedra and phosphate tetrahedra fits that in crandallite, but the layer separation is expanded in response to location of Mg2(H2O)10 edge-shared octahedral dimers and H2O molecules within the interlayer. The structure related penriceite is formed via periodic unit-cell-scale twinning of the structure of elliottite.
Represents a new type of crandallite-derivative layered structure. Topology of Al-centred corner-sharing octahedra and phosphate tetrahedra fits that in crandallite, but the layer separation is expanded in response to location of Mg2(H2O)10 edge-shared octahedral dimers and H2O molecules within the interlayer. The structure related penriceite is formed via periodic unit-cell-scale twinning of the structure of elliottite.
Unique Identifiers
Mindat ID:
55923
Long-form identifier:
mindat:1:1:55923:8
Similar Names
| Aleutite | A valid IMA mineral species | [Cu5O2](AsO4)(VO4) · (Cu,K,Pb,Rb,Cs,)Cl |
| Aleutite (rock) | A rock subtype | |
| Aliettite | A valid IMA mineral species | Ca0.2Mg6((Si,Al)8O20)(OH)4 · 4H2O |
| Eulitite | A synonym of Eulytine |
IMA Classification of Elliottite
Approved
IMA Formula:
NaMgAl3(PO4)2F6·9H2O
Approval year:
2022
First published:
2022
Approval history:
IMA 2021-113 approved and published as elliottite in CNMNC Newsletter 66, February - March 2022.
Classification of Elliottite
8.DM.
8 : PHOSPHATES, ARSENATES, VANADATES
D : Phosphates, etc. with additional anions, with H2O
M : With large and medium-sized cations, (OH, etc.):RO4 > 2:1
8 : PHOSPHATES, ARSENATES, VANADATES
D : Phosphates, etc. with additional anions, with H2O
M : With large and medium-sized cations, (OH, etc.):RO4 > 2:1
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 |
|---|---|---|
| Elli | 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 Elliottite
Transparency:
Transparent
Colour:
Colorless. White in aggregates.
Streak:
White
Cleavage:
Perfect
On {001}.
On {001}.
Density:
2.09 g/cm3 (Calculated)
Comment:
Calculated using the empirical formula.
Optical Data of Elliottite
Type:
Biaxial (+)
RI values:
nα = 1.475(2) nβ = 1.475(2) nγ = 1.479(2)
Birefringence:
not observed (in the view normal to the plates)
Max. Birefringence:
δ = 0.004
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:
Moderate (negative)
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.
No measured or calculated 2V is on file for this mineral, so the value used here (0°) is estimated from its recorded refractive indices and optic sign, not from a direct 2V measurement.
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.
No measured or calculated 2V is on file for this mineral, so the value used here (0°) is estimated from its recorded refractive indices and optic sign, not from a direct 2V measurement.
Pleochroism:
Not Visible
Comments:
Orientation: Z ≈ c; strong pseudo-uniaxial optical behaviour.
Chemistry of Elliottite
Mindat Formula:
NaMgAl3(PO4)2F6 · 9H2O
Element Weights:
Crystallography of Elliottite
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
B2/m
Setting:
C2/m
Cell Parameters:
a = 12.242(1) Å, b = 7.0118(7) Å, c = 11.2946(9) Å
β = 101.19(1)°
β = 101.19(1)°
Ratio:
a:b:c = 1.746 : 1 : 1.611
Unit Cell V:
951.08 ų (Calculated from Unit Cell)
Morphology:
Ultra-thin pseudohexagonal platelets.
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 11.08 Å | (100) |
| 6.059 Å | (9) |
| 5.782 Å | (12) |
| 5.532 Å | (10) |
| 5.106 Å | (31) |
| 3.346 Å | (6) |
| 2.882 Å | (8) |
| 2.852 Å | (17) |
Type Occurrence of Elliottite
General Appearance of Type Material:
Pseudohexagonal platelets, forming hemispherical aggregates up to 1 mm across; the aggregates overgrow minyulite and angastonite, on a matrix of goethite.
Place of Conservation of Type Material:
The holotype specimen is housed in the mineralogical collections of the South Australia Museum, North Terrace, Adelaide, SA 5000, Australia, catalogue number G35026,a sub-sample of the holotype specimen, used for optical measurements, is in the collections of the Natural History Museum of Los Angeles County, catalogue number 76203. Co-type specimen M45575 is a portion of the type specimen for angastonite, housed at Museum of Victoria,GPO Box 666, Melbourne, Vic 3001, Australia, catalogue number M45575 (cotype).
Geological Setting of Type Material:
Phosphate deposit as an alteration of minyulite in near-neutral solution.
Associated Minerals at Type Locality:
Synonyms of Elliottite
Other Language Names for Elliottite
Dutch:Elliottiet
German:Elliottit
Common Associates
Associations Based on Photo Data:
| 1 photo of Elliottite associated with Minyulite | KAl2(PO4)2F · 4H2O |
| 1 photo of Elliottite associated with Tomsquarryite | NaMgAl3(PO4)2(OH)6 · 8H2O |
| 1 photo of Elliottite associated with Penriceite | [Mg(H2O)6][Na(H2O)2Al3(PO4)2F6] · H2O |
Related Minerals - Strunz-mindat Grouping
| 8.DM. | Tomsquarryite | NaMgAl3(PO4)2(OH)6 · 8H2O |
| 8.DM. | Betpakdalite-FeFe | [Fe3+2 (H2O)15(OH)2Fe3+(H2O)6][Mo8As2Fe3+3O37] |
| 8.DM. | Penriceite | [Mg(H2O)6][Na(H2O)2Al3(PO4)2F6] · H2O |
| 8.DM. | Betpakdalite-CaMg | [Ca2(H2O)17Mg(H2O)6][Mo8As2Fe3+3O36(OH)] |
| 8.DM. | Chinnerite | [Mg(H2O)6]Na(H2O)2Al3(PO4)2F6 |
| 8.DM. | Sarrochite | [Ca4(H2O)38][Mo8P2Fe3+3O37(OH)] |
| 8.DM.05 | Esperanzaite | NaCa2Al2(AsO4)2(OH)F4 · 2H2O |
| 8.DM.05 | Morinite | NaCa2Al2(PO4)2(OH)F4 · 2H2O |
| 8.DM.10 | Alexshubnikovite | Ca2Cu9(AsO4)4(OH)9Cl(H2O)8 · 2H2O |
| 8.DM.10 | Tangdanite | Ca2Cu9(AsO4)4(SO4)0.5(OH)9 · 9H2O |
| 8.DM.10 | Tyrolite | Ca2Cu9(AsO4)4(CO3)(OH)8 · 11H2O |
| 8.DM.15 | Melkovite | [Ca2(H2O)15Ca(H2O)6][Mo8P2Fe3+3O36(OH)] |
| 8.DM.15 | Betpakdalite-NaCa | [Na2(H2O)17Ca(H2O)6][Mo6+8As5+2Fe3+3O34(OH)3] |
| 8.DM.15 | Betpakdalite-CaCa | [Ca2(H2O)17Ca(H2O)6][Mo6+8As5+2Fe3+3O36(OH)] |
| 8.DM.20 | Phosphovanadylite-Ba | Ba[V4+4P2O8(OH)8] · 12H2O |
| 8.DM.20 | Phosphovanadylite-Ca | Ca[V4+4P2O12(OH)4] · 12H2O |
| 8.DM.25 | Yukonite | Ca3Fe3+(AsO4)2(OH)3 · 5H2O |
| 8.DM.30 | Uduminelite | Ca3Al8(PO4)2O12 · 2H2O |
| 8.DM.35 | Aldermanite | [Mg(H2O)6][Na(H2O)2Al3(PO4)2(OH,F)6] · H2O |
| 8.DM.35 | 'Azovskite' | Fe3+3(PO4)(OH)6 or near |
| 8.DM.35 | Delvauxite | CaFe4(PO4,SO4)2(OH)8 · 4-6H2O not confirmed |
| 8.DM.40 | Santafeite | (Na,Ca,Sr)12(Mn2+,Fe3+,Al,Mg)8Mn4+8(VO4)16(OH,O)20 · 8H2O |
| 8.DM.55 | Tapiaite | Ca5Al2(AsO4)4(OH)4 · 12H2O |
| 8.DM.60 | Alcantarillaite | [Fe3+0.5(H2O)4][CaAs3+2(Fe3+2.5W6+0.5)(AsO4)2O7] |
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 Elliottite
mindat.org URL:
https://www.mindat.org/min-55923.html
Please feel free to link to this page.
Please feel free to link to this page.
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References for Elliottite
Reference List:
Grey, Ian Edward, Elliott, Peter, Mumme, William Gus, MacRae, Colin M., Kampf, Anthony R., Mills, Stuart J. (2022) Redefinition of angastonite, CaMgAl2(PO4)2(OH)4 ⋅ 7H2O, as an amorphous mineral. European Journal of Mineralogy, 34 (2) 215-221 doi:10.5194/ejm-34-215-2022
Miyawaki, Ritsuro, Hatert, Frédéric, Pasero, Marco, Mills, Stuart J. (2022) IMA Commission on New Minerals, Nomenclature and Classification (CNMNC) – Newsletter 66. European Journal of Mineralogy, 34 (2) 253-257 doi:10.5194/ejm-34-253-2022
Localities for Elliottite
Showing 2 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.
Australia | |
| Grey et al. (2022) |
| Grey et al. (2022) |
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Penrice marble quarry, Penrice, Barossa Council, South Australia, Australia