Straczekite
A valid IMA mineral species
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About Straczekite
Formula:
(Ca,K,Ba)(V5+,V4+)8O20 · 3H2O
Colour:
Green-black
Lustre:
Greasy
Hardness:
1 - 2
Specific Gravity:
3.09 - 3.29
Crystal System:
Monoclinic
Member of:
Name:
Named in honor of John A. Straczek (13 September 1914, Washington, USA - 2 November 2003, Connecticut, USA), chief geologist, Union Carbide Corporation, who made possible the study of the mineral. Pronounced strā'chek-ite. *Birth/death details, other than birth year, unverified.
This page provides mineralogical data about Straczekite.
Unique Identifiers
Mindat ID:
3796
Long-form identifier:
mindat:1:1:3796:5
IMA Classification of Straczekite
Approved
IMA Formula:
(Ca,K,Ba)V4+2V5+6O20·3H2O
Approval year:
1983
First published:
1984
Classification of Straczekite
4.HE.20
4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
H : V[5,6] Vanadates
E : Phyllovanadates
4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
H : V[5,6] Vanadates
E : Phyllovanadates
47.3.2.1
47 : VANADIUM OXYSALTS
3 : Hydrated Normal Vanadium Oxysalts
47 : VANADIUM OXYSALTS
3 : Hydrated Normal Vanadium Oxysalts
21.2.15
21 : Vanadates (and vanadates with arsenate or phosphate)
2 : Vanadates of Mg, Ca, Sr or Ba
21 : Vanadates (and vanadates with arsenate or phosphate)
2 : Vanadates of Mg, Ca, Sr or Ba
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 |
|---|---|---|
| Szk | 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 Straczekite
Greasy
Transparency:
Opaque
Colour:
Green-black
Streak:
Greenish black
Hardness:
1 - 2 on Mohs scale
Cleavage:
Perfect
{100}
{100}
Density:
3.09 - 3.29 g/cm3 (Measured) 3.21 g/cm3 (Calculated)
Optical Data of Straczekite
Type:
Biaxial (-)
RI values:
nα = 2
Surface Relief:
Unknown
Dispersion:
relatively weak
Pleochroism:
Weak
Comments:
apple-green to olive-green
Chemistry of Straczekite
Mindat Formula:
(Ca,K,Ba)(V5+,V4+)8O20 · 3H2O
Element Weights:
Crystallography of Straczekite
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
B2/m
Setting:
C2/m
Cell Parameters:
a = 11.679(3) Å, b = 3.6608(4) Å, c = 10.636(2) Å
β = 100.53(4)°
β = 100.53(4)°
Ratio:
a:b:c = 3.19 : 1 : 2.905
Unit Cell V:
447.08 ų (Calculated from Unit Cell)
Z:
1
Twinning:
On {001}, possible, observed by X-ray diffraction.
Crystal Structure
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Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
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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) |
|---|---|---|---|---|---|---|---|
| 0010852 | Straczekite | Kutoglu A (1983) Kristallstruktur der calcium-vanadium-bronze CaxV4+2xV5+(2-2x)O5 Zeitschrift fur Kristallographie 162 263-272 |  | 1983 | synthetic | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 10.449 Å | (50) |
| 3.486 Å | (100) |
| 3.255 Å | (10) |
| 2.492 Å | (10) |
| 1.9437 Å | (15) |
| 1.8306 Å | (50) |
| 1.8030 Å | (10) |
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] | |
| 47h : [Near-surface oxidized, dehydrated minerals] |
Type Occurrence of Straczekite
General Appearance of Type Material:
Dark greenish-black crystals as thin laths up to 0.5 mm in length, forming thick masses.
Place of Conservation of Type Material:
No designated type material.
Geological Setting of Type Material:
A rare secondary mineral in fibrous seams in gangue.
Associated Minerals at Type Locality:
Synonyms of Straczekite
Other Language Names for Straczekite
Relationship of Straczekite to other Species
Member of:
Other Members of Straczekite Group:
| Bariandite | Al0.6(V5+,V4+)8O20 · 9H2O | Mon. |
| Bokite | (Al,Fe)1.3(V5+,V4+,Fe3+)8O20 · 7.5H2O | Mon. |
| Corvusite | (Na,K,Ca,Mg)2(V5+,V4+,Fe2+)8O20 · 6-10H2O | Mon. 2/m : B2/m |
| Fernandinite | (Ca,K)(V5+,V4+,Fe2+)8O20 · 10H2O | Mon. 2/m : B2/m |
Common Associates
Associations Based on Photo Data:
| 11 photos of Straczekite associated with Miserite | K1.5-x(Ca,Y,REE)5(Si6O15)(Si2O7)(OH,F)2 · yH2O |
| 11 photos of Straczekite associated with Wollastonite | Ca3(Si3O9) |
| 1 photo of Straczekite associated with Francevillite | Ba(UO2)2(VO4)2 · 5H2O |
| 1 photo of Straczekite associated with Quartz | SiO2 |
| 1 photo of Straczekite associated with Calcite | CaCO3 |
Related Minerals - Strunz-mindat Grouping
| 4.HE.05 | Melanovanadite | Ca(V5+,V4+)4O10 · 5H2O |
| 4.HE.10 | Shcherbinaite | V5+2O5 |
| 4.HE.15 | Hewettite | CaV6O16 · 9H2O |
| 4.HE.15 | Metahewettite | CaV6O16 · 3H2O |
| 4.HE.20 | Bariandite | Al0.6(V5+,V4+)8O20 · 9H2O |
| 4.HE.20 | Corvusite | (Na,K,Ca,Mg)2(V5+,V4+,Fe2+)8O20 · 6-10H2O |
| 4.HE.20 | Bokite | (Al,Fe)1.3(V5+,V4+,Fe3+)8O20 · 7.5H2O |
| 4.HE.20 | Fernandinite | (Ca,K)(V5+,V4+,Fe2+)8O20 · 10H2O |
| 4.HE.25 | Häggite | V3+V4+O2(OH)3 |
| 4.HE.30 | Doloresite | V4+3O4(OH)4 |
| 4.HE.35 | Duttonite | V4+O(OH)2 |
| 4.HE.40 | Cavoite | CaV4+3O7 |
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 Straczekite
mindat.org URL:
https://www.mindat.org/min-3796.html
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References for Straczekite
Reference List:
Evans, Howard T., Nord, Gordon, Marinenko, John, Milton, Charles (1984) Straczekite, a new calcium barium potassium vanadate mineral from Wilson Springs, Arkansas. Mineralogical Magazine, 48 (347) 289-293 doi:10.1180/minmag.1984.048.347.16
Dunn, Pete J., Fleischer, Michael, Langley, Richard H., Shigley, James E., Zilczer, Janet A. (1985) New mineral names. American Mineralogist, 70 (7-8) 871-881
Localities for Straczekite
Showing 4 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.
Germany | |
| Witzke et al. (2001) |
USA | |
| Evans et al. (1990) +1 other reference |
| Howard +2 other references |
|
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North Wilson pit, Union Carbide Mine, Wilson Springs, Garland County, Arkansas, USA