Gatewayite
A valid IMA mineral species
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About Gatewayite
Formula:
Ca6(As3+V4+3 V5+9As5+6O51) · 31H2O
Colour:
Very dark greenish blue
Lustre:
Vitreous
Hardness:
2
Specific Gravity:
2.34
Crystal System:
Monoclinic
Member of:
Name:
Named for the Gateway mining district that includes the type locality. Gateway is also the nearest town to the Packrat mine.
Related to vanarsite and packratite. The other polyoxometalate from the same site is, e.g., kegginite.
Unique Identifiers
Mindat ID:
46572
Long-form identifier:
mindat:1:1:46572:6
IMA Classification of Gatewayite
Approved
IMA Formula:
Ca6(As3+V4+3V5+9As5+6O51)·31H2O
Approval year:
2015
First published:
2016
Type description reference:
Classification of Gatewayite
8.FD.10
8 : PHOSPHATES, ARSENATES, VANADATES
F : Polyphosphates, Polyarsenates, [4]-Polyvanadates
D : Polyphosphates, etc., with OH and H2O
8 : PHOSPHATES, ARSENATES, VANADATES
F : Polyphosphates, Polyarsenates, [4]-Polyvanadates
D : Polyphosphates, etc., with OH and H2O
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 |
|---|---|---|
| Gwy | 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 Gatewayite
Vitreous
Transparency:
Transparent
Colour:
Very dark greenish blue
Streak:
Grayish blue
Hardness:
2 on Mohs scale
Tenacity:
Brittle
Cleavage:
Imperfect/Fair
{010} and {101} fair
{010} and {101} fair
Density:
2.34(2) g/cm3 (Measured) 2.337 g/cm3 (Calculated)
Optical Data of Gatewayite
Type:
Biaxial (-)
RI values:
nα = 1.621(1) nβ = 1.654(5) nγ = 1.668(5)
2V:
Measured: 65.9° (9), Calculated: 65.0°
Max. Birefringence:
δ = 0.047
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 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:
Extreme
Comments:
X pale olive green, Y medium greenish blue, Z dark greenish blue; X < < Y < Z
Comments:
Y = b, X^a ≈ 30° in obtuse β
Chemistry of Gatewayite
Mindat Formula:
Ca6(As3+V4+3 V5+9As5+6O51) · 31H2O
Element Weights:
Crystallography of Gatewayite
Crystal System:
Monoclinic
Class (H-M):
2 - Sphenoidal
Space Group:
P21
Setting:
P21
Cell Parameters:
a = 11.1850(4) Å, b = 16.8528(4) Å, c = 20.7146(15) Å
β = 91.166(6)°
β = 91.166(6)°
Ratio:
a:b:c = 0.664 : 1 : 1.229
Unit Cell V:
3903.9 ų
Z:
2
Morphology:
Blades, more or less flattened on {101} and elongated on [010].
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
Remove metal-metal sticks
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) |
|---|---|---|---|---|---|---|---|
| M12046 | Gatewayite | Kampf, Anthony R., Hughes, John M., P. Nash, Barbara, Marty, Joe (2016) Vanarsite, packratite, morrisonite, and gatewayite: four new minerals containing the [As3+V4+,5+12As5+6O51] heteropolyanion, a novel polyoxometalate cluster. The Canadian Mineralogist, 54 (1) 145-162 doi:10.3749/canmin.1500062 | 2016 | Packrat Mine, Colorado, USA | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 13.16 Å | (47) |
| 11.13 Å | (8) |
| 9.70 Å | (100) |
| 3.246 Å | (9) |
| 2.953 Å | (9) |
| 2.866 Å | (14) |
| 2.810 Å | (17) |
| 2.758 Å | (9) |
Reference:
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 7: Great Oxidation Event | <2.4 |
| 47a : [Near-surface hydration of prior minerals] | |
| 47d : [Arsenates, antimonates, selenates, bismuthinates] | |
| 47e : [Vanadates, chromates, manganates] |
Type Occurrence of Gatewayite
General Appearance of Type Material:
Blades up to 0.5 mm long in divergent inter-growths. Also as crude prisms, up to 1 mm long, with rounded faces and as composite crystals consisting of subparallel inter-growths of narrow prisms up to 2 mm long.
Place of Conservation of Type Material:
Co-type material is deposited in the collections of the Natural History Museum of Los Angeles County, Los Angeles, California, USA, catalogue numbers 64513, 64514, 65555 and 65559
Geological Setting of Type Material:
On montroseite- and corvusite-bearing sandstone. Oxidation of montroseite-corvusite assemblage in a moist environment.
Associated Minerals at Type Locality:
Reference:
Synonyms of Gatewayite
Other Language Names for Gatewayite
Dutch:Gatewayiet
German:Gatewayit
Relationship of Gatewayite to other Species
Member of:
Other Members of Vanarsite Group:
| Lumsdenite | NaCa3Mg2(As3+V4+2V5+10As5+6O51) · 45H2O | Tric. 1 : P1 |
| Morrisonite | Ca11(As3+V4+2V5+10As5+6O51)2 · 78H2O | Mon. 2/m : P21/b |
| Packratite | Ca11(As3+V5+10V4+2As5+6O51)2 · 83H2O | Tric. 1 : P1 |
| Vanarsite | NaCa12(As3+V5+8.5V4+3.5As5+6O51)2 · 78H2O | Mon. 2/m : P21/b |
Common Associates
Associations Based on Photo Data:
| 1 photo of Gatewayite associated with Magnesiopascoite | Ca2Mg(V10O28) · 16H2O |
| 1 photo of Gatewayite associated with Zincocabrerite | ZnMg2(AsO4)2(H2O)8 |
Related Minerals - Strunz-mindat Grouping
| 8.FD.05 | Volborthite | Cu3(V2O7)(OH)2 · 2H2O |
| 8.FD.05 | Martyite | Zn3(V2O7)(OH)2 · 2H2O |
| 8.FD.05 | Karpenkoite | Co3(V2O7)(OH)2 · 2H2O |
| 8.FD.10 | Vanarsite | NaCa12(As3+V5+8.5V4+3.5As5+6O51)2 · 78H2O |
| 8.FD.10 | Packratite | Ca11(As3+V5+10V4+2As5+6O51)2 · 83H2O |
| 8.FD.10 | Bicapite | [KNa2Mg2(H2O)25][H2PV5+12O40(V5+O)2] |
| 8.FD.10 | Morrisonite | Ca11(As3+V4+2V5+10As5+6O51)2 · 78H2O |
| 8.FD.10 | Lumsdenite | NaCa3Mg2(As3+V4+2V5+10As5+6O51) · 45H2O |
| 8.FD.10 | Kegginite | Pb3Ca3[AsV12O40(VO)] · 20H2O |
| 8.FD.15 | Chinchorroite | Na2Mg5(As2O7)2(AsO3OH)2(H2O)10 |
Fluorescence of Gatewayite
None
Other Information
Notes:
Insoluble in room-temperature H2O; easily soluble in room-temperature dilute HCl.
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 Gatewayite
mindat.org URL:
https://www.mindat.org/min-46572.html
Please feel free to link to this page.
Please feel free to link to this page.
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External Links:
Mineral Dealers:
References for Gatewayite
Reference List:
Hålenius, U., Hatert, F., Pasero, M., Mills, S. J. (2015) New minerals and nomenclature modifications approved in 2015, CNMNC Newsletter No 24. Mineralogical Magazine, 79 (2) 247-251 doi:10.1180/minmag.2015.079.2.03
Localities for Gatewayite
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.
USA (TL) | |
| Hålenius et al. (2015) +2 other references |
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Packrat Mine, Beaver Mesa, Gateway Mining District, Mesa County, Colorado, USA