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Caseyite

A valid IMA mineral species
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About CaseyiteHide

06592570017271953577624.jpg
William H. Casey
Formula:
[(V5+O2)Al10-x(OH)20-2x(H2O)18-2x]2[H2V4+V5+9O28][V5+10O28]2(Na,K,Ca)2-y(SO4)2-z · (60+8x+y+4z)H2O (x = 0-2.5; y = 0-2; z = 0-2)
previously given as [(V5+O2)Al7.5(OH)15(H2O)13]2[H2V4+V5+9O28][V5+10O28]2·90H2O
Colour:
Yellow
Lustre:
Vitreous
Hardness:
2 - 3
Specific Gravity:
2.151 (Calculated)
Crystal System:
Monoclinic
Name:
Named in honor of William H. Casey (b. 1955, San Francisco, California, USA), chemistry professor in the University of California Davis College of Letters and Science, for his work on vanadium compounds and polyoxometalates. He has made major contributions in the fields of aqueous geochemistry and inorganic solution chemistry, and has received multiple awards and medals.
New structure type. It is related to structures based on flat-Al13 polyoxometalate cation.


Unique IdentifiersHide

Mindat ID:
53574
Long-form identifier:
mindat:1:1:53574:2

Classification of CaseyiteHide

00669880017683444897551.jpg
The Decavanadate Cluster

The decavanadate cluster found in caseyite. The same cluster is known in a number of other secondary vanadium minerals including, for example, pascoite, magnesiopascoite, and gunterite. Caseyite also exhibits a modified decavanadate cluster where one of the V5+ atoms is replaced by a V4+ and the cluster is doubly protonated, as well as a larger cluster mostly made up of linked corner and edge-sharing AlO6 octahedra.

IMA Classification of CaseyiteHide

Approved
IMA Formula:
[(V5+O2)Al7.5(OH)15(H2O)13]2[H2V4+V5+9O28][V5+10O28]2·90H2O
Approval year:
2019
First published:
2020
4.HC.30

4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
H : V[5,6] Vanadates
C : [6]-Sorovanadates

Mineral SymbolsHide

As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.

SymbolSourceReference for Standard
CsyIMA–CNMNCWarr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43

Physical Properties of CaseyiteHide

Vitreous
Colour:
Yellow
Streak:
Pale yellow streak
Hardness:
2 - 3 on Mohs scale
Tenacity:
Brittle
Cleavage:
None Observed
Fracture:
Conchoidal
Density:
2.151 g/cm3 (Calculated)

Optical Data of CaseyiteHide

Type:
Biaxial (+)
RI values:
nα = 1.659(3) nβ = 1.670(3) nγ = 1.720(3)
2V:
Measured: 52.6° (5)
Max. Birefringence:
δ = 0.061
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.

Surface Relief:
Very High (positive)
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.
Dispersion:
Strong
Pleochroism:
Non-pleochroic

Chemistry of CaseyiteHide

Mindat Formula:
[(V5+O2)Al10-x(OH)20-2x(H2O)18-2x]2[H2V4+V5+9O28][V5+10O28]2(Na,K,Ca)2-y(SO4)2-z · (60+8x+y+4z)H2O (x = 0-2.5; y = 0-2; z = 0-2)

previously given as [(V5+O2)Al7.5(OH)15(H2O)13]2[H2V4+V5+9O28][V5+10O28]2·90H2O
Element Weights:
Element% weight
O53.593 %
V31.563 %
Al10.449 %
H2.264 %
S1.242 %
Na0.890 %

Calculated from ideal end-member formula.
O
V
Al
H
S
Na

Crystallography of CaseyiteHide

Crystal System:
Monoclinic
Cell Parameters:
a = 14.123(8) Å, b = 31.00(1) Å, c = 21.95(1) Å
β = 97.961(8)°
Ratio:
a:b:c = 0.456 : 1 : 0.708
Unit Cell V:
9516 ų
Z:
2
Comment:
P21/n

Crystal StructureHide

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IDSpeciesReferenceLinkYearLocalityPressure (GPa)Temp (K)
M11968CaseyiteKampf, A.R., Cooper, M.A., Hughes, J.M., Nash, B.P., Hawthorne, F.C., Marty, J. (2020) Caseyite Kampf, Anthony R., Cooper, Mark A., Hughes, John M., Nash, Barbara P., Hawthorne, Frank C., Marty, Joe Caseyite, a new mineral containing a variant of the flat-Al13 polyoxometalate cation. American Mineralogist, 105 (1) 123-131 doi:10.2138/am-2020-20200293
CIF Raw Data - click here to close

X-Ray Powder DiffractionHide

Geological EnvironmentHide

Paragenetic Mode(s):

Type Occurrence of CaseyiteHide

General Appearance of Type Material:
Tapering needles or blades
Place of Conservation of Type Material:
In the collections of the Natural History Museum of Los Angeles County, Los Angeles, USA, catalogue numbers 73526 (Packrat – holotype), 73527 and 73528 (Packrat –cotypes),73529 (West Sunday – cotype), 73530 and 73531 (Burro – cotypes)

Synonyms of CaseyiteHide

Other Language Names for CaseyiteHide

Dutch:Caseyiet
German:Caseyit

Relationship of Caseyite to other SpeciesHide

Other Members of Pascoite Family:
Ammoniolasalite[(NH4)2Mg2(H2O)20] [V10O28]Mon. 2/m : B2/b
BluestreakiteK4Mg2(V4+2V5+8O28) · 14H2OMon. 2/m
BurroiteCa2(NH4)2(V10O28) · 15H2OTric. 1 : P1
Flatimerite[Al13(OH)24(H2O)24][V5+9V4+O28] · [(SO4)4(H2O)24]Tric. 1 : P1
GunteriteNa4Ca(V10O28) · 20H2OMon. 2/m : B2/m
HuemuliteNa4Mg(V10O28) · 24H2OTric.
HughesiteNa3Al(V10O28) · 22H2OTric. 1 : P1
HummeriteK2Mg2(V10O28) · 16H2OTric. 1 : P1
HydropascoiteCa3(V10O28) · 24H2OTric. 1 : P1
KokinositeNa2Ca2(V10O28) · 24H2OTric. 1 : P1
LasaliteNa2Mg2(V10O28) · 20H2OMon. 2/m : B2/b
MagnesiopascoiteCa2Mg(V10O28) · 16H2OMon. 2/m : B2/m
NashiteNa3Ca2[(V5+9V4+)O28] · 24H2OMon. 2/m : P21/m
OkieiteMg3[V10O28] · 28H2OTric. 1 : P1
PascoiteCa2Ca(V10O28) · 17H2OMon. 2 : B2
PostiteMg(H2O)6Al2(OH)2(H2O)8(V10O28) · 13H2OOrth. mmm(2/m2/m2/m) : Pccn
Protocaseyite[Al4(OH)6(H2O)12][V10O28] · 8H2OTric. 1 : P1
Rakovanite(NH4)3Na3(V10O28) · 12H2OMon. 2/m
Schindlerite{(NH4)4Na2(H2O)10}{V10O28}Tric. 1 : P1
TrebiskyiteNa3Mg2[TiV9O28] · 22H2OMon. 2/m : P21/b
Wernerbaurite{(NH4)2[Ca2(H2O)14](H2O)2}{V10O28}Tric. 1 : P1

Common AssociatesHide

Associations Based on Photo Data:
1 photo of Caseyite associated with GypsumCaSO4 · 2H2O

Related Minerals - Strunz-mindat GroupingHide

4.HC.Protocaseyite[Al4(OH)6(H2O)12][V10O28] · 8H2OTric. 1 : P1
4.HC.Ammoniolasalite[(NH4)2Mg2(H2O)20] [V10O28]Mon. 2/m : B2/b
4.HC.BeckettiteCa2V6Al6O20Tric. 1 : P1
4.HC.05PascoiteCa2Ca(V10O28) · 17H2OMon. 2 : B2
4.HC.05HydropascoiteCa3(V10O28) · 24H2OTric. 1 : P1
4.HC.05LasaliteNa2Mg2(V10O28) · 20H2OMon. 2/m : B2/b
4.HC.05HughesiteNa3Al(V10O28) · 22H2OTric. 1 : P1
4.HC.05MagnesiopascoiteCa2Mg(V10O28) · 16H2OMon. 2/m : B2/m
4.HC.05Rakovanite(NH4)3Na3(V10O28) · 12H2OMon. 2/m
4.HC.10HummeriteK2Mg2(V10O28) · 16H2OTric. 1 : P1
4.HC.15SherwooditeCa5.5(AlV4+V5+12O39) · 28H2OTet. 4/mmm(4/m2/m2/m) : I41/amd
4.HC.20BluestreakiteK4Mg2(V4+2V5+8O28) · 14H2OMon. 2/m
4.HC.25Wernerbaurite{(NH4)2[Ca2(H2O)14](H2O)2}{V10O28}Tric. 1 : P1
4.HC.25BurroiteCa2(NH4)2(V10O28) · 15H2OTric. 1 : P1
4.HC.35GunteriteNa4Ca(V10O28) · 20H2OMon. 2/m : B2/m
4.HC.40KokinositeNa2Ca2(V10O28) · 24H2OTric. 1 : P1
4.HC.45NashiteNa3Ca2[(V5+9V4+)O28] · 24H2OMon. 2/m : P21/m
4.HC.50OkieiteMg3[V10O28] · 28H2OTric. 1 : P1
4.HC.55PostiteMg(H2O)6Al2(OH)2(H2O)8(V10O28) · 13H2OOrth. mmm(2/m2/m2/m) : Pccn
4.HC.60Schindlerite{(NH4)4Na2(H2O)10}{V10O28}Tric. 1 : P1

Other InformationHide

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 CaseyiteHide

References for CaseyiteHide

Localities for CaseyiteHide

Showing 3 localities.

This map shows a selection of localities that have latitude and longitude coordinates recorded. Click on the symbol to view information about a locality. The symbol next to localities in the list can be used to jump to that position on the map.
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Locality ListHide

- 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). Struck out - Mineral was erroneously reported from this locality. Faded * - Never found at this locality but inferred to have existed at some point in the past (e.g. from pseudomorphs).

All localities listed without proper references should be considered as questionable.
USA (TL)
 
  • Colorado
    • Mesa County
      • Gateway Mining District
        • Beaver Mesa
Kampf et al. (2020)
    • San Miguel County
Kampf et al. (2020)
    • Slick Rock Mining District
Kampf et al. (2020)
 
and/or  
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