Gunterite
A valid IMA mineral species
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Formula:
Na4Ca(V10O28) · 20H2O
the original formula, Na4(H2O)16(H2V10O28)•6H2O, was revised and changed in 2021 (Newsletter #61, proposal 21-B)
Colour:
Orange-yellow
Lustre:
Sub-Adamantine
Hardness:
1
Specific Gravity:
2.398 (Calculated)
Crystal System:
Monoclinic
Member of:
Name:
Named in honor of Dr. Mickey Eugene Gunter (b. 1953), Professor of Mineralogy at the University of Idaho. Professor Gunter is particularly well known for his studies in optical mineralogy and the mineralogy of asbestos minerals.
Type Locality:
This page provides mineralogical data about Gunterite.
Unique Identifiers
Mindat ID:
42440
Long-form identifier:
mindat:1:1:42440:0
Similar Names
Classification of Gunterite
The decavanadate cluster found in gunterite. The same cluster is known in a number of other secondary vanadium minerals including, for example, rakovanite, postite, and hughesite.
IMA Classification of Gunterite
Approved
IMA status notes:
Redefined by the IMA
IMA Formula:
Na4Ca[V5+10O28]·20H2O
Approval year:
2011
First published:
2011
Approval history:
The original formula, Na4(H2O)16(H2V10O28)•6H2O, was revised and changed in 2021 (CNMNC Newsletter #61, proposal 21-B).
4.HC.35
4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
H : V[5,6] Vanadates
C : [6]-Sorovanadates
4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
H : V[5,6] Vanadates
C : [6]-Sorovanadates
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 |
|---|---|---|
| Gun | 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 Gunterite
Sub-Adamantine
Transparency:
Transparent, Translucent
Colour:
Orange-yellow
Streak:
Yellow
Hardness:
1 on Mohs scale
Tenacity:
Brittle
Cleavage:
None Observed
Parting:
none
Fracture:
Irregular/Uneven
Density:
2.398 g/cm3 (Calculated)
Optical Data of Gunterite
Type:
Biaxial (+)
RI values:
nα = 1.735(5) nβ = 1.770(5) nγ = 1.825(5)
2V:
Measured: 78°
Max. Birefringence:
δ = 0.090
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
Dispersion:
v < r, strong, parallel
Optical Extinction:
X = b, Y ≈ c.
Pleochroism:
Visible
Comments:
X = yellow; Y = orange; Z yellow.
Comments:
γ calculated (index fluids decomposed mineral)
Absorption: Y > X > Z.
Absorption: Y > X > Z.
Chemistry of Gunterite
Mindat Formula:
Na4Ca(V10O28) · 20H2O
the original formula, Na4(H2O)16(H2V10O28)•6H2O, was revised and changed in 2021 (Newsletter #61, proposal 21-B)
the original formula, Na4(H2O)16(H2V10O28)•6H2O, was revised and changed in 2021 (Newsletter #61, proposal 21-B)
Element Weights:
Crystallography of Gunterite
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
B2/m
Setting:
C2/m
Cell Parameters:
a = 19.848(2) Å, b = 10.1889(11) Å, c = 13.1184(15) Å
β = 130.187(9)°
β = 130.187(9)°
Ratio:
a:b:c = 1.948 : 1 : 1.288
Unit Cell V:
2,026.68 ų (Calculated from Unit Cell)
Z:
2
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) |
|---|---|---|---|---|---|---|---|
| 0018627 | Gunterite | Kampf A R, Hughes J M, Marty J, Nash B (2011) Gunterite, Na4(H2O)16(H2V10O28)*6H2O, a new mineral species with a doubly-protonated decavanadate polyanion: crystal structure and descriptive mineralogy The Canadian Mineralogist 49 1243-1251 | 2011 | West Sunday mine, San Miguel County, Colorado, USA | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 10.01 Å | (100) |
| 8.44 Å | (72) |
| 8.09 Å | (46) |
| 2.997 Å | (29) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 7: Great Oxidation Event | <2.4 |
| 47a : [Near-surface hydration of prior minerals] | |
| 47e : [Vanadates, chromates, manganates] | |
| Stage 10b: Anthropogenic minerals | <10 Ka |
| 55 : Anthropogenic mine minerals |
Type Occurrence of Gunterite
General Appearance of Type Material:
Tabular on {001} and generally stacked into elongate curved multiple crystals up to 0.5 mm in maximum dimension. The crystals typically exhibit warping and, in some cases, skeletal growth features.
Place of Conservation of Type Material:
Natural History Museum of Los Angeles County under catalogue numbers 63506 and 63507.
Geological Setting of Type Material:
Efflorescences on the sandstone walls of the mine workings and in fractures in the sandstone forming from the
oxidation of montroseite–corvusite assemblages.
oxidation of montroseite–corvusite assemblages.
Associated Minerals at Type Locality:
Synonyms of Gunterite
Other Language Names for Gunterite
Relationship of Gunterite to other Species
Member of:
Other Members of Pascoite Family:
| Ammoniolasalite | [(NH4)2Mg2(H2O)20] [V10O28] | Mon. 2/m : B2/b |
| Bluestreakite | K4Mg2(V4+2V5+8O28) · 14H2O | Mon. 2/m |
| Burroite | Ca2(NH4)2(V10O28) · 15H2O | Tric. 1 : P1 |
| Caseyite | [(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) | Mon. |
| Flatimerite | [Al13(OH)24(H2O)24][V5+9V4+O28] · [(SO4)4(H2O)24] | Tric. 1 : P1 |
| Huemulite | Na4Mg(V10O28) · 24H2O | Tric. |
| Hughesite | Na3Al(V10O28) · 22H2O | Tric. 1 : P1 |
| Hummerite | K2Mg2(V10O28) · 16H2O | Tric. 1 : P1 |
| Hydropascoite | Ca3(V10O28) · 24H2O | Tric. 1 : P1 |
| Kokinosite | Na2Ca2(V10O28) · 24H2O | Tric. 1 : P1 |
| Lasalite | Na2Mg2(V10O28) · 20H2O | Mon. 2/m : B2/b |
| Magnesiopascoite | Ca2Mg(V10O28) · 16H2O | Mon. 2/m : B2/m |
| Nashite | Na3Ca2[(V5+9V4+)O28] · 24H2O | Mon. 2/m : P21/m |
| Okieite | Mg3[V10O28] · 28H2O | Tric. 1 : P1 |
| Pascoite | Ca2Ca(V10O28) · 17H2O | Mon. 2 : B2 |
| Postite | Mg(H2O)6Al2(OH)2(H2O)8(V10O28) · 13H2O | Orth. mmm(2/m2/m2/m) : Pccn |
| Protocaseyite | [Al4(OH)6(H2O)12][V10O28] · 8H2O | Tric. 1 : P1 |
| Rakovanite | (NH4)3Na3(V10O28) · 12H2O | Mon. 2/m |
| Schindlerite | {(NH4)4Na2(H2O)10}{V10O28} | Tric. 1 : P1 |
| Trebiskyite | Na3Mg2[TiV9O28] · 22H2O | Mon. 2/m : P21/b |
| Wernerbaurite | {(NH4)2[Ca2(H2O)14](H2O)2}{V10O28} | Tric. 1 : P1 |
Related Minerals - Strunz-mindat Grouping
| 4.HC. | Protocaseyite | [Al4(OH)6(H2O)12][V10O28] · 8H2O |
| 4.HC. | Ammoniolasalite | [(NH4)2Mg2(H2O)20] [V10O28] |
| 4.HC. | Beckettite | Ca2V6Al6O20 |
| 4.HC.05 | Pascoite | Ca2Ca(V10O28) · 17H2O |
| 4.HC.05 | Hydropascoite | Ca3(V10O28) · 24H2O |
| 4.HC.05 | Lasalite | Na2Mg2(V10O28) · 20H2O |
| 4.HC.05 | Hughesite | Na3Al(V10O28) · 22H2O |
| 4.HC.05 | Magnesiopascoite | Ca2Mg(V10O28) · 16H2O |
| 4.HC.05 | Rakovanite | (NH4)3Na3(V10O28) · 12H2O |
| 4.HC.10 | Hummerite | K2Mg2(V10O28) · 16H2O |
| 4.HC.15 | Sherwoodite | Ca5.5(AlV4+V5+12O39) · 28H2O |
| 4.HC.20 | Bluestreakite | K4Mg2(V4+2V5+8O28) · 14H2O |
| 4.HC.25 | Wernerbaurite | {(NH4)2[Ca2(H2O)14](H2O)2}{V10O28} |
| 4.HC.25 | Burroite | Ca2(NH4)2(V10O28) · 15H2O |
| 4.HC.30 | Caseyite | [(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) |
| 4.HC.40 | Kokinosite | Na2Ca2(V10O28) · 24H2O |
| 4.HC.45 | Nashite | Na3Ca2[(V5+9V4+)O28] · 24H2O |
| 4.HC.50 | Okieite | Mg3[V10O28] · 28H2O |
| 4.HC.55 | Postite | Mg(H2O)6Al2(OH)2(H2O)8(V10O28) · 13H2O |
| 4.HC.60 | Schindlerite | {(NH4)4Na2(H2O)10}{V10O28} |
Fluorescence of Gunterite
Not fluorescent.
Other Information
Notes:
Soluble in water at room temperature.
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 Gunterite
mindat.org URL:
https://www.mindat.org/min-42440.html
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References for Gunterite
Reference List:
Kampf, A. R., Hughes, J. M., Marty, J., Nash, B. (2011) Gunterite, Na4(H2O)16(H2V10O28)·6H2O, a new mineral species with a doubly-protonated decavanadate polyanion: crystal structure and descriptive mineralogy. The Canadian Mineralogist, 49 (5) 1243-1251 doi:10.3749/canmin.49.5.1243
Williams, P. A., Hatert, F., Pasero, M., Mills, S. J. (2011) New minerals and nomenclature modifications approved in 2011. CNMNC Newsletter No 9. Mineralogical Magazine, 75 (4) 2535-2540 doi:10.1180/minmag.2011.075.4.2535
Localities for Gunterite
Showing 3 localities.
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 | |
| Kampf et al. (2019) |
| www.handbookofmineralogy.org (2015) |
| Kampf et al. (2011) +1 other reference |
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