Steigerite
A valid IMA mineral species - grandfathered
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About Steigerite
George Steiger
Formula:
Al(VO4) · 3H2O
Colour:
Canary-yellow, greenish yellow, olive-green
Lustre:
Waxy
Hardness:
2½ - 3
Specific Gravity:
2.52 - 2.58
Crystal System:
Monoclinic
Name:
Named in honor of George Steiger (27 May 1869, Columbia, Pennsylvania, USA - 18 April 1944, Washington, D.C., USA), Chief Chemist, United States Geological Survey, Washington, D.C., USA.
A secondary mineral occurring either as impregnations in sandstones or as a weathering product from vanadium-rich schists.
Unique Identifiers
Mindat ID:
3759
Long-form identifier:
mindat:1:1:3759:0
IMA Classification of Steigerite
Approved, 'Grandfathered' (first described prior to 1959)
IMA Formula:
AlV5+O4·3H2O
Classification of Steigerite
8.CE.65
8 : PHOSPHATES, ARSENATES, VANADATES
C : Phosphates without additional anions, with H2O
E : With only medium-sized cations, RO4:H2O about 1:2.5
8 : PHOSPHATES, ARSENATES, VANADATES
C : Phosphates without additional anions, with H2O
E : With only medium-sized cations, RO4:H2O about 1:2.5
40.4.5.1
40 : HYDRATED NORMAL PHOSPHATES,ARSENATES AND VANADATES
4 : (AB)5(XO4)2·xH2O
40 : HYDRATED NORMAL PHOSPHATES,ARSENATES AND VANADATES
4 : (AB)5(XO4)2·xH2O
21.3.1
21 : Vanadates (and vanadates with arsenate or phosphate)
3 : Vanadates of Al, rare earths, Pb, V or Bi
21 : Vanadates (and vanadates with arsenate or phosphate)
3 : Vanadates of Al, rare earths, Pb, V or Bi
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 |
|---|---|---|
| Sgr | 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 Steigerite
Waxy
Transparency:
Translucent
Comment:
Lustre waxy in compact aggregates
Colour:
Canary-yellow, greenish yellow, olive-green
Hardness:
2½ - 3 on Mohs scale
Tenacity:
Fragile
Cleavage:
Perfect
On {010}, perfect; on {100}, fair.
On {010}, perfect; on {100}, fair.
Density:
2.52 - 2.58 g/cm3 (Measured) 2.58 g/cm3 (Calculated)
Optical Data of Steigerite
Type:
Biaxial (+)
RI values:
nα = 1.72 - 1.73 nβ = 1.73 - 1.734 nγ = 1.748 - 1.752
Max. Birefringence:
δ = 0.022 - 0.028
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:
Very 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.
No measured or calculated 2V is on file for this mineral, so the value used here (64°) 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 (64°) is estimated from its recorded refractive indices and optic sign, not from a direct 2V measurement.
Dispersion:
relatively strong
Chemistry of Steigerite
Mindat Formula:
Al(VO4) · 3H2O
Element Weights:
Elements listed:
Crystallography of Steigerite
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
P21/m
Cell Parameters:
a = 11.84 Å, b = 25 Å, c = 11.04 Å
β = 111.17°
β = 111.17°
Ratio:
a:b:c = 0.474 : 1 : 0.442
Unit Cell V:
3,047.30 ų (Calculated from Unit Cell)
Z:
24
Morphology:
Cryptocrystalline fibrous, may be flat platy {010} Gumlike to compact massive, commonly as powdery coatings.
Comment:
Class is either 2/ or 2; space group is either P21/m or P21.
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 2.93 Å | (100) |
| 12.52 Å | (50) |
| 2.18 Å | (50) |
| 1.897 Å | (50) |
| 1.758 Å | (50) |
| 3.09 Å | (40) |
| 2.21 Å | (40) |
Comments:
Kara-Tau Mountains, Kazakhstan.
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] |
Type Occurrence of Steigerite
General Appearance of Type Material:
Fracture cotings
Place of Conservation of Type Material:
U.S. National Museum of Natural History, Washington, D.C., USA: #C5108.
Geological Setting of Type Material:
Nodular concretions of Corvusite in sandstone.
Associated Minerals at Type Locality:
Other Language Names for Steigerite
Varieties of Steigerite
| Chromsteigerite | A Cr-bearing variety of steigerite. |
Common Associates
Associations Based on Photo Data:
| 2 photos of Steigerite associated with Barnesite | (Na,Ca)V6O16 · 3H2O |
| 2 photos of Steigerite associated with Gypsum | CaSO4 · 2H2O |
| 2 photos of Steigerite associated with Vanoxite | V4+4V5+2O13 · 8H2O |
| 1 photo of Steigerite associated with Bokite | (Al,Fe)1.3(V5+,V4+,Fe3+)8O20 · 7.5H2O |
| 1 photo of Steigerite associated with Fervanite | Fe3+4V5+4O16 · 5H2O |
| 1 photo of Steigerite associated with Corvusite | (Na,K,Ca,Mg)2(V5+,V4+,Fe2+)8O20 · 6-10H2O |
| 1 photo of Steigerite associated with 'Petrified Wood' |
Related Minerals - Strunz-mindat Grouping
| 8.CE. | Monteneroite | Cu2+Mn2+2(AsO4)2 · 8H2O |
| 8.CE. | Belmonteite | CaMn2(AsO4)2 · 7H2O |
| 8.CE.X | Babánekite | Cu3(AsO4)2 · 8H2O |
| 8.CE.05 | Chudobaite | Mg5(AsO4)2(AsO3OH)2 · 10H2O |
| 8.CE.05 | Geigerite | Mn2+5(AsO4)2(HAsO4)2 · 10H2O |
| 8.CE.10 | Newberyite | Mg(PO3OH) · 3H2O |
| 8.CE.10 | Manganonewberyite | Mn(PO3OH)(H2O)3 |
| 8.CE.15 | Fanguangite | (MoO2)(PO3OH) · 4H2O |
| 8.CE.15 | Brassite | Mg(HAsO4) · 4H2O |
| 8.CE.20 | Phosphorrösslerite | Mg(PO3OH) · 7H2O |
| 8.CE.20 | Rösslerite | Mg(HAsO4) · 7H2O |
| 8.CE.25 | Switzerite | Mn2+3(PO4)2 · 7H2O |
| 8.CE.25 | Metaswitzerite | Mn2+3(PO4)2 · 4H2O |
| 8.CE.30 | Pradetite | CoCu4(AsO4)2(HAsO4)2 · 9H2O |
| 8.CE.30 | Veselovskýite | ZnCu4(AsO4)2(HAsO4)2 · 9H2O |
| 8.CE.30 | Lindackerite | CuCu4(AsO4)2(HAsO4)2 · 9H2O |
| 8.CE.30 | Klajite | MnCu4(AsO4)2(HAsO4)2 · 9-10H2O |
| 8.CE.30 | Hloušekite | (Ni,Co)Cu4(AsO4)2(AsO3OH)2 · 9H2O |
| 8.CE.30 | Ondrušite | CaCu4(AsO4)2(HAsO4)2 · 10H2O |
| 8.CE.35 | Bobierrite | Mg3(PO4)2 · 8H2O |
| 8.CE.40 | Barićite | (Mg,Fe)3(PO4)2 · 8H2O |
| 8.CE.40 | Parasymplesite | Fe2+3(AsO4)2 · 8H2O |
| 8.CE.40 | Gritsenkoite | CoMg2(AsO4)2(H2O)8 |
| 8.CE.40 | Cabrerite | NiMg2(AsO4)2 · 8H2O |
| 8.CE.40 | Pakhomovskyite | Co3(PO4)2 · 8H2O |
| 8.CE.40 | Vivianite | Fe2+Fe2+2(PO4)2 · 8H2O |
| 8.CE.40 | Arupite | Ni3(PO4)2 · 8H2O |
| 8.CE.40 | Erythrite | Co3(AsO4)2 · 8H2O |
| 8.CE.40 | Hörnesite | Mg3(AsO4)2 · 8H2O |
| 8.CE.40 | Manganohörnesite | Mn2+3(AsO4)2 · 8H2O |
| 8.CE.40 | Köttigite | Zn3(AsO4)2 · 8H2O |
| 8.CE.40 | Ferrisymplesite | Fe3+3(AsO4)2(OH)3 · 5H2O |
| 8.CE.40 | Annabergite | Ni3(AsO4)2 · 8H2O |
| 8.CE.45 | Symplesite | Fe2+3(AsO4)2 · 8H2O |
| 8.CE.50 | Cattiite | Mg3(PO4)2 · 22H2O |
| 8.CE.55 | Koninckite | Fe3+PO4 · 3H2O |
| 8.CE.60 | Kaňkite | FeAsO4 · 3.5H2O |
| 8.CE.60 | Hilarionite | Fe3+2(SO4)(AsO4)(OH) · 6H2O |
| 8.CE.70 | Metaschoderite | Al2(PO4)(VO4) · 6H2O |
| 8.CE.70 | Schoderite | Al2(PO4)(VO4) · 8H2O |
| 8.CE.75 | Zigrasite | MgZr(PO4)2 · 4H2O |
| 8.CE.75 | 'UM2009-11-PO:CaHZr' | CaZr[PO4]2 · 4H2O |
| 8.CE.75 | Malhmoodite | FeZr(PO4)2 · 4H2O |
| 8.CE.80 | Santabarbaraite | Fe3+3(PO4)2(OH)3 · 5H2O |
| 8.CE.85 | Metaköttigite | (Zn,Fe,Fe)3(AsO4)2 · 8(H2O,OH) |
| 8.CE.90 | Slavkovite | Cu13(AsO4)6(AsO3OH)4 · 23H2O |
Other Information
Notes:
Readily soluble in dilute mineral acids to a deep cherry-red solution. Insoluble in water.
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 Steigerite
mindat.org URL:
https://www.mindat.org/min-3759.html
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Please feel free to link to this page.
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References for Steigerite
Localities for Steigerite
Showing 11 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.
Kazakhstan | |
| Fleischer (1959) +1 other reference |
| Amer.Mineral. (1961) |
| Evseev (1995) +1 other reference |
USA | |
| Weeks et al. (1955) +3 other references |
| Eckel et al. (1997) |
| Eckel et al. (1997) | |
| Eckel et al. (1997) |
| Eckel et al. (1997) |
| Henderson (1935) +1 other reference | |
| Bullock (1981) |
| Collected and analyzed by Joy Desor. |
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Cactus Rat Mine, The Poison Strip, Thompsons Mining District, Grand County, Utah, USA