Kaňkite (original) (raw)
A valid IMA mineral species
About KaňkiteHide
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Colour:
Yellowish green, paler greenish yellow on exposure to air; very pale grayish yellow to pale yellow in transmitted light
Specific Gravity:
2.60 - 2.70
Crystal System:
Monoclinic
Name:
Named for the type locality.
Related to and easily confused with hilarionite. Compare 'UM1979-03-AsO:Fe' and 'UM1979-04-AsO:Fe'.
Often associated with bukovskýite.
Crystal structure not yet solved, as the mineral decomposes in vacuum to Fe2(AsO4)(HAsO4)(OH)(H2O), that equals FeAsO4.2H2O. The crystal structure of this phase (space group Cc) has corrugated sheets of heteropolyhedra. The building unit comprises a pair of Fe-bearing octahedra decorated by 5 arsenate tetrahedra. Kaňkite dehydrates to FeAsO4.2H2O at 55–56°C. Its structure is supposed to be similar to the above described, in terms of the presence of corrugated sheets (Majzlan et al., 2016).
Unique IdentifiersHide
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Long-form identifier:
mindat:1:1:2153:7
a65131df-185a-4cab-b403-224c112509e2
IMA Classification of KaňkiteHide
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IMA Formula:
Fe3+(AsO4) · 3.5H2O
Classification of KaňkiteHide
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8.CE.60
8 : PHOSPHATES, ARSENATES, VANADATES
C : Phosphates without additional anions, with H2O
E : With only medium-sized cations, RO4:H2O about 1:2.5
40.5.4.
40 : HYDRATED NORMAL PHOSPHATES,ARSENATES AND VANADATES
5 : AXO4·xH2O
20.9.3
20 : Arsenates (also arsenates with phosphate, but without other anions)
9 : Arsenates of Fe
Mineral SymbolsHide
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As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
Please only use the official IMA–CNMNC symbol. Older variants are listed for historical use only.
| Symbol | Source | Reference |
|---|---|---|
| Kňk | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
| Knk | The Canadian Mineralogist (2019) | The Canadian Mineralogist (2019) The Canadian Mineralogist list of symbols for rock- and ore-forming minerals (December 30, 2019). download |
Physical Properties of KaňkiteHide
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Colour:
Yellowish green, paler greenish yellow on exposure to air; very pale grayish yellow to pale yellow in transmitted light
Fracture:
Irregular/Uneven
Density:
2.60 - 2.70 g/cm3 (Measured) 2.732 g/cm3 (Calculated)
Optical Data of KaňkiteHide
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RI values:
_n_α = 1.664(2) _n_γ = 1.680(2)
δ = 0.016
Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.
Chemistry of KaňkiteHide
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Mindat Formula:
FeAsO4 · 3.5H2O
Crystallography of KaňkiteHide
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Crystal System:
Monoclinic
Class (H-M):
2 - Sphenoidal
Cell Parameters:
a = 18.803(15) Å, b = 17.490(18) Å, c = 7.633(5) Å
β = 92.71(5)°
Ratio:
a:b:c = 1.075 : 1 : 0.436
Unit Cell V:
2,507.42 ų (Calculated from Unit Cell)
X-Ray Powder DiffractionHide
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Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 12.8 Å | (100) |
| 7.56 Å | (25) |
| 7.22 Å | (21) |
| 4.764 Å | (34) |
| 4.258 Å | (25) |
| 3.697 Å | (22b) |
| 2.630 Å | (29) |
Geological EnvironmentHide
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Type Occurrence of KaňkiteHide
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General Appearance of Type Material:
Yellowish-green botryoidal coatings and crusts to 7 mm thick.
Place of Conservation of Type Material:
Charles University, Prague, Czech Republic, 20135.
National Museum of Natural History, Washington, D.C., USA, 144939.
Geological Setting of Type Material:
An alteration product of arsenopyrite.
Associated Minerals at Type Locality:
Other Language Names for KaňkiteHide
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Common AssociatesHide
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Associated Minerals Based on Photo Data:
Related Minerals - Strunz-mindat GroupingHide
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Other InformationHide
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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 KaňkiteHide
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References for KaňkiteHide
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Reference List:
Dunn, Pete J., Chao, George Y., Fleischer, Michael, Ferraiolo, James A., Langley, Richard H., Pabst, Adolf, Zilczer, Janet A. (1985) New mineral names. American Mineralogist, 70 (1-2) 214-221
Localities for KaňkiteHide
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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.
Locality ListHide
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- 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.