Walentaite
A valid IMA mineral species
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About Walentaite
Prof. Dr. Kurt Walenta
Formula:
[Mn2+(H2O)6][◻As3+3Fe3+3(PO4)2O7]
Revised by Grey et al. (2019)
Colour:
Bright yellow
Lustre:
Vitreous
Hardness:
3
Specific Gravity:
2.72
Crystal System:
Orthorhombic
Member of:
Name:
Named in honor of Dr. Kurt Walenta (1 December 1927 Prague, Czech Republic - 19 November 2021), Professor of Mineralogy, University of Stuttgart (Germany), who made significant contributions to the mineralogy of arsenates and phosphates, especially from the Schwarzwald (Black Forest), Germany.
Unique combination of elements. One of 3 known minerals with arsenate and phosphate anions occupying separate structural positions (compare machatschkiite and epifanovite).
Compare natrowalentaite.
Walentaite has been redefined and shown to have 89% of its As as As(III) and not As(V). Ca, Na, Mn, and Fe(II) atoms are located in the interlayer space.
Its structure has trimeric As3+3O6 units.
Structurally related to alcantarillaite.
Compare natrowalentaite.
Walentaite has been redefined and shown to have 89% of its As as As(III) and not As(V). Ca, Na, Mn, and Fe(II) atoms are located in the interlayer space.
Its structure has trimeric As3+3O6 units.
Structurally related to alcantarillaite.
Unique Identifiers
Mindat ID:
4235
Long-form identifier:
mindat:1:1:4235:8
IMA Classification of Walentaite
Approved
IMA status notes:
Redefined by the IMA
Approval year:
1983
First published:
1984
Approval history:
Redefined IMA 2020 s.p.: Grey et al (2019).
Classification of Walentaite
8.CH.05
8 : PHOSPHATES, ARSENATES, VANADATES
C : Phosphates without additional anions, with H2O
H : With large and medium-sized cations, RO4:H2O < 1:1
8 : PHOSPHATES, ARSENATES, VANADATES
C : Phosphates without additional anions, with H2O
H : With large and medium-sized cations, RO4:H2O < 1:1
40.5.10.1
40 : HYDRATED NORMAL PHOSPHATES,ARSENATES AND VANADATES
5 : AXO4·xH2O
40 : HYDRATED NORMAL PHOSPHATES,ARSENATES AND VANADATES
5 : AXO4·xH2O
20.9.17
20 : Arsenates (also arsenates with phosphate, but without other anions)
9 : Arsenates of Fe
20 : Arsenates (also arsenates with phosphate, but without other anions)
9 : Arsenates of Fe
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 |
|---|---|---|
| Wlt | 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 Walentaite
Vitreous
Transparency:
Translucent
Colour:
Bright yellow
Streak:
Pale yellow
Hardness:
3 on Mohs scale
Tenacity:
Brittle
Cleavage:
Perfect
On {010}
On {010}
Density:
2.72 g/cm3 (Measured) 2.72 g/cm3 (Calculated)
Optical Data of Walentaite
Type:
Biaxial (+)
Dispersion:
r > v moderate (type description says dispersion not discernible).
Optical Extinction:
Z = c, Y = a.
Pleochroism:
Weak
Comments:
Z = medium yellow-green, Y = pale yellow green.
Comments:
Absorption: Z < Y.
2V could not be measured.
2V could not be measured.
Chemistry of Walentaite
Mindat Formula:
[Mn2+(H2O)6][◻As3+3Fe3+3(PO4)2O7]
Revised by Grey et al. (2019)
Revised by Grey et al. (2019)
Element Weights:
General Formula
Fe33+(P0.84As0.16O4)2(O,OH)6As3+2.56Ca0.42Na0.28Mn2+0.35Fe2+0.30O6.1(OH)0.9(H2O)0.9
Outdated empirical formula. Formerly given as H(Ca,Mn2+,Fe2+)Fe3+3(AsO4,PO4)4.7H2O
Outdated empirical formula. Formerly given as H(Ca,Mn2+,Fe2+)Fe3+3(AsO4,PO4)4.7H2O
Crystallography of Walentaite
Crystal System:
Orthorhombic
Class (H-M):
mmm(2/m2/m2/m) - Dipyramidal
Space Group:
Imma
Setting:
Imma
Cell Parameters:
a = 26.188(5) Å, b = 7.360(2) Å, c = 10.367(2) Å
Ratio:
a:b:c = 3.558 : 1 : 1.409
Unit Cell V:
1,998.17 ų (Calculated from Unit Cell)
Morphology:
Type material: Bladed crystals approximately 20 x 60 x 1-2 µm in size that are elongate on [001] and flattened perpendicular to b so that {010} is the dominant form. Aggregates forming rosettes.
Crystal Structure
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Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
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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) |
|---|---|---|---|---|---|---|---|
| 0020839 | Walentaite | Grey I E, Mumme W G, Hochleitner R (2019) Trimeric As3+3O6 clusters in walentaite: crystal structure and revised formula European Journal of Mineralogy 31 111-116 | 2019 | White Elephant mine, Pringle, South Dakota, USA | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 12.9 Å | (100) |
| 3.00 Å | (50) |
| 4.43 Å | (30) |
| 6.56 Å | (20) |
| 4.82 Å | (20) |
| 2.931 Å | (20) |
| 2.776 Å | (20) |
Comments:
White Elephant mine, South Dakota, USA. Data from the type description.
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 7: Great Oxidation Event | <2.4 |
| 47a : [Near-surface hydration of prior minerals] | |
| 47c : [Carbonates, phosphates, borates, nitrates] | |
| 47d : [Arsenates, antimonates, selenates, bismuthinates] |
Type Occurrence of Walentaite
General Appearance of Type Material:
Rosette-like aggregates of thin, bladed crystals approximately 20 x 60 x 1-2 µm in size.
Place of Conservation of Type Material:
The Natural History Museum, London, England, 1984,690.
National Museum of Natural History, Washington, D.C., USA, 149782, 149783.
National Museum of Natural History, Washington, D.C., USA, 149782, 149783.
Geological Setting of Type Material:
Complex zoned pegmatite.
Associated Minerals at Type Locality:
Synonyms of Walentaite
Other Language Names for Walentaite
Relationship of Walentaite to other Species
Member of:
Other Members of Walentaite Subgroup:
| Natrowalentaite | [Fe3+0.5Na0.5(H2O)6][NaAs3+2(Fe3+2.33W6+0.67)(PO4)2O7] | Orth. mmm(2/m2/m2/m) : Imma |
Common Associates
Associations Based on Photo Data:
| 2 photos of Walentaite associated with Löllingite | FeAs2 |
Related Minerals - Strunz-mindat Grouping
| 8.CH.05 | Natrowalentaite | [Fe3+0.5Na0.5(H2O)6][NaAs3+2(Fe3+2.33W6+0.67)(PO4)2O7] |
| 8.CH.05 | Halilsarpite | [Mg(H2O)6][CaAs3+2(Fe3+2.67Mo6+0.33)(AsO4)2O7] |
| 8.CH.10 | Anapaite | Ca2Fe2+(PO4)2 · 4H2O |
| 8.CH.15 | Picropharmacolite | Ca4Mg(AsO4)2(HAsO4)2 · 11H2O |
| 8.CH.20 | Dittmarite | (NH4)Mg(PO4) · H2O |
| 8.CH.20 | Niahite | (NH4)Mn2+(PO4) · H2O |
| 8.CH.25 | Taranakite | K3Al5(PO3OH)6(PO4)2 · 18H2O |
| 8.CH.25 | Francoanellite | K3Al5(PO3OH)6(PO4)2 · 12H2O |
| 8.CH.25 | Macivorite | (NH4)3Al5(PO3OH)6(PO4)2 · 18H2O |
| 8.CH.30 | Schertelite | (NH4)2MgH2(PO4)2 · 4H2O |
| 8.CH.35 | Hannayite | (NH4)2Mg3H4(PO4)4 · 8H2O |
| 8.CH.40 | Hazenite | KNaMg2(PO4)2 · 14H2O |
| 8.CH.40 | Struvite-(K) | KMg(PO4) · 6H2O |
| 8.CH.40 | Struvite | (NH4)Mg(PO4) · 6H2O |
| 8.CH.45 | Rimkorolgite | (Mg,Mn)5(Ba,Sr,Ca)(PO4)4 · 8H2O |
| 8.CH.50 | Bakhchisaraitsevite | Na2Mg5(PO4)4 · 7H2O |
| 8.CH.55 | Smolyaninovite | Co3Fe3+2(AsO4)4 · 11H2O |
| 8.CH.55 | Fahleite | CaZn5Fe3+2(AsO4)6 · 14H2O |
| 8.CH.60 | Barahonaite-(Fe) | (Ca,Cu,Na,Fe3+,Al)12Fe3+2(AsO4)8(OH,Cl)x · nH2O |
| 8.CH.60 | Barahonaite-(Al) | (Ca,Cu,Na,Fe3+,Al)12Al2(AsO4)8(OH,Cl)x · nH2O |
| 8.CH.70 | Epifanovite | NaCaCu5(PO4)4[AsO2(OH)2] · 7H2O |
| 8.CH.75 | Esdanaite-(Ce) | NaMnCe(PO4)2 · 4H2O |
Fluorescence of Walentaite
Not fluorescent.
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 Walentaite
mindat.org URL:
https://www.mindat.org/min-4235.html
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Please feel free to link to this page.
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References for Walentaite
Localities for Walentaite
Showing 6 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.
Australia | |
| Nickel (1987) |
Morocco | |
| Favreau et al. (2006) |
Spain | |
| www.foro-minerales.com (n.d.) |
USA | |
| |
| Marco Ciriotti collection (analysed by SEM-EDS, 2005) |
| Dunn et al. (1984) |
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White Elephant Mine, Cicero Peak, Pringle, Custer Mining District, Custer County, South Dakota, USA