Weddellite (original) (raw)
A valid IMA mineral species - grandfathered
About WeddelliteHide
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Formula:
Ca(C2O4) · (2.5-x)H2O
0 ≤ x ≤ 0.25
Previously reported as CaC2O4·2H2O and CaC2O4·(2+x)H2O
Colour:
Colourless, white, yellowish brown to brown; colourless in transmitted light.
Lustre:
Vitreous, Silky, Dull
Crystal System:
Tetragonal
Name:
Named after its discovery locality, the Weddell Sea, Antarctica. The first natural and non-biologically produced material was described by Bannister and Hey (1936), but they did not name it. Frondel and Prien (1942) used the name weddellite for the first time but gave no data.
Authigenic in bottom sediments and peat; in calcareous lacustrine sediments; also formed by reaction of calcite with oxalic acid derived from lichens; also from solutions derived from bat guano. Known as component of human urinary stones. May also be produced by fungi (e.g., Burford et al., 2003; compare 'Unnamed (Pb Oxalate Dihydrate)'); as such is found in soils and leaf litter; also formed by lichens liivng on basalts, serpentinites, Cu-bearing rocks, gabbroes, dolerites, andesites, volcanic clasts; examples of organisms producing it are numerous, with Acarospora rugulosa, Geastrum spp. and Lecidea lactea, to mention some.
NOTE: Cleaning of any specimens with oxalic acid will lead to crystallisation of whewellite or weddellite if Ca-bearing soluble species are present on the specimen.
Contains zeolitic water. May occur in coral reefs. These observations, as well as confirmation of an additional water site, and the current formula, are taken from Mills & Christy (2016).
Unique IdentifiersHide
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Long-form identifier:
mindat:1:1:4254:9
1cb867d8-1046-4767-9fce-255b3097c15e
IMA Classification of WeddelliteHide
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Approved, 'Grandfathered' (first described prior to 1959)
IMA Formula:
Ca(C2O4) · 2H2O
Type description reference:
Classification of WeddelliteHide
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10.AB.40
10 : ORGANIC COMPOUNDS
A : Salts of organic acids
B : Oxalates
50.1.2.1
50 : ORGANIC COMPOUNDS
1 : Oxalates
31.1.6
31 : Oxalates, Citrates, Mellitates and Acetates
1 : Oxalates
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.
| Symbol | Source | Reference |
|---|---|---|
| Wed | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
Pronunciation of WeddelliteHide
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Pronunciation:
| Play | Recorded by | Country |
|---|---|---|
| Sorry, your browser doesn't support HTML5 audio. | Jolyon Ralph | United Kingdom |
Physical Properties of WeddelliteHide
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Colour:
Colourless, white, yellowish brown to brown; colourless in transmitted light.
Cleavage:
None Observed
Mandarino and Witt (1983) report a good {010} cleavage, unlike other descriptions.
Density:
1.94 g/cm3 (Measured) 1.962 g/cm3 (Calculated)
Optical Data of WeddelliteHide
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RI values:
_n_ω = 1.523 _n_ε = 1.544
δ = 0.021
Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.
Chemistry of WeddelliteHide
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Mindat Formula:
Ca(C2O4) · (2.5-x)H2O
0 ≤ x ≤ 0.25
Previously reported as CaC2O4·2H2O and CaC2O4·(2+x)H2O
Crystallography of WeddelliteHide
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Crystal System:
Tetragonal
Class (H-M):
4/m - Dipyramidal
Cell Parameters:
a = 12.371 Å, c = 7.357 Å
Unit Cell V:
1,125.93 ų (Calculated from Unit Cell)
Morphology:
Crystals commonly isolated, with {011}, elongated [010], terminated by {001}; commonly corroded.
Twinning:
Single or multiple twins possibly noted.
Crystal StructureHide
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| ID | Species | Reference | Link | Year | Locality | Pressure (GPa) | Temp (K) |
|---|---|---|---|---|---|---|---|
| 0000777 | Weddellite | Tazzoli V, Domeneghetti M C (1980) The crystal structures of whewellite and weddellite: re-examination and comparison American Mineralogist 65 327-334 |  |
1980 | 0 | 293 | |
| 0020071 | Weddellite | Izatulina A, Gurzhiy V, Frank-Kamenetskaya O (2014) Weddellite from renal stones: Structure refinement and dependence of crystal chemical features on H2O content. American Mineralogist 99 2-7 | 2014 | oxalic renal stones of St. Petersburg citizens aged 24-65 years | 0 | 293 | |
| 0020072 | Weddellite | Izatulina A, Gurzhiy V, Frank-Kamenetskaya O (2014) Weddellite from renal stones: Structure refinement and dependence of crystal chemical features on H2O content. American Mineralogist 99 2-7 | 2014 | oxalic renal stones of St. Petersburg citizens aged 24-65 years | 0 | 293 | |
| 0020073 | Weddellite | Izatulina A, Gurzhiy V, Frank-Kamenetskaya O (2014) Weddellite from renal stones: Structure refinement and dependence of crystal chemical features on H2O content. American Mineralogist 99 2-7 | 2014 | oxalic renal stones of St. Petersburg citizens aged 24-65 years | 0 | 293 | |
| 0020074 | Weddellite | Izatulina A, Gurzhiy V, Frank-Kamenetskaya O (2014) Weddellite from renal stones: Structure refinement and dependence of crystal chemical features on H2O content. American Mineralogist 99 2-7 | 2014 | oxalic renal stones of St. Petersburg citizens aged 24-65 years | 0 | 293 | |
| 0020075 | Weddellite | Izatulina A, Gurzhiy V, Frank-Kamenetskaya O (2014) Weddellite from renal stones: Structure refinement and dependence of crystal chemical features on H2O content. American Mineralogist 99 2-7 | 2014 | oxalic renal stones of St. Petersburg citizens aged 24-65 years | 0 | 293 | |
| 0020076 | Weddellite | Izatulina A, Gurzhiy V, Frank-Kamenetskaya O (2014) Weddellite from renal stones: Structure refinement and dependence of crystal chemical features on H2O content. American Mineralogist 99 2-7 | 2014 | oxalic renal stones of St. Petersburg citizens aged 24-65 years | 0 | 293 | |
| 0020077 | Weddellite | Izatulina A, Gurzhiy V, Frank-Kamenetskaya O (2014) Weddellite from renal stones: Structure refinement and dependence of crystal chemical features on H2O content. American Mineralogist 99 2-7 | 2014 | oxalic renal stones of St. Petersburg citizens aged 24-65 years | 0 | 293 | |
| 0020078 | Weddellite | Izatulina A, Gurzhiy V, Frank-Kamenetskaya O (2014) Weddellite from renal stones: Structure refinement and dependence of crystal chemical features on H2O content. American Mineralogist 99 2-7 | 2014 | oxalic renal stones of St. Petersburg citizens aged 24-65 years | 0 | 293 | |
| 0020079 | Weddellite | Izatulina A, Gurzhiy V, Frank-Kamenetskaya O (2014) Weddellite from renal stones: Structure refinement and dependence of crystal chemical features on H2O content. American Mineralogist 99 2-7 | 2014 | oxalic renal stones of St. Petersburg citizens aged 24-65 years | 0 | 293 | |
| 0020080 | Weddellite | Izatulina A, Gurzhiy V, Frank-Kamenetskaya O (2014) Weddellite from renal stones: Structure refinement and dependence of crystal chemical features on H2O content. American Mineralogist 99 2-7 | 2014 | oxalic renal stones of St. Petersburg citizens aged 24-65 years | 0 | 293 | |
| 0020081 | Weddellite | Izatulina A, Gurzhiy V, Frank-Kamenetskaya O (2014) Weddellite from renal stones: Structure refinement and dependence of crystal chemical features on H2O content. American Mineralogist 99 2-7 | 2014 | oxalic renal stones of St. Petersburg citizens aged 24-65 years | 0 | 293 | |
| 0020082 | Weddellite | Izatulina A, Gurzhiy V, Frank-Kamenetskaya O (2014) Weddellite from renal stones: Structure refinement and dependence of crystal chemical features on H2O content. American Mineralogist 99 2-7 | 2014 | oxalic renal stones of St. Petersburg citizens aged 24-65 years | 0 | 293 | |
| 0020083 | Weddellite | Izatulina A, Gurzhiy V, Frank-Kamenetskaya O (2014) Weddellite from renal stones: Structure refinement and dependence of crystal chemical features on H2O content. American Mineralogist 99 2-7 | 2014 | oxalic renal stones of St. Petersburg citizens aged 24-65 years | 0 | 293 | |
| 0020084 | Weddellite | Izatulina A, Gurzhiy V, Frank-Kamenetskaya O (2014) Weddellite from renal stones: Structure refinement and dependence of crystal chemical features on H2O content. American Mineralogist 99 2-7 | 2014 | oxalic renal stones of St. Petersburg citizens aged 24-65 years | 0 | 293 | |
| 0020085 | Weddellite | Izatulina A, Gurzhiy V, Frank-Kamenetskaya O (2014) Weddellite from renal stones: Structure refinement and dependence of crystal chemical features on H2O content. American Mineralogist 99 2-7 | 2014 | oxalic renal stones of St. Petersburg citizens aged 24-65 years | 0 | 293 | |
| 0020086 | Weddellite | Izatulina A, Gurzhiy V, Frank-Kamenetskaya O (2014) Weddellite from renal stones: Structure refinement and dependence of crystal chemical features on H2O content. American Mineralogist 99 2-7 | 2014 | oxalic renal stones of St. Petersburg citizens aged 24-65 years | 0 | 293 | |
| 0020087 | Weddellite | Izatulina A, Gurzhiy V, Frank-Kamenetskaya O (2014) Weddellite from renal stones: Structure refinement and dependence of crystal chemical features on H2O content. American Mineralogist 99 2-7 | 2014 | oxalic renal stones of St. Petersburg citizens aged 24-65 years | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder DiffractionHide
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Image Loading
Radiation - Copper Kα
Data Set:
Data courtesy of RRUFF project at University of Arizona, used with permission.
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 2.744 Å | (100) |
| 6.19 Å | (72) |
| 3.35 Å | (66) |
| 2.231 Å | (63) |
| 1.892 Å | (49) |
| 4.43 Å | (40) |
| 2.792 Å | (38) |
Geological EnvironmentHide
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Geological Setting:
Authigenic in bottom sediments and peat; in calcareous lacustrine sediments; also formed by reaction of calcite with oxalic acid derived from lichens; also from solutions derived from bat guano.
Type Occurrence of WeddelliteHide
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General Appearance of Type Material:
Place of Conservation of Type Material:
The Natural History Museum, London, England: #1936,975 to 1936,977.
Geological Setting of Type Material:
Bottom muds of an Antarctic sea.
Synonyms of WeddelliteHide
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Other Language Names for WeddelliteHide
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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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Fluorescence of WeddelliteHide
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Can fluoresce yellow under long-wave UV.
Other InformationHide
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Notes:
Dehydrates to Whewellite upon exposure to air. 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 WeddelliteHide
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References for WeddelliteHide
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Reference List:
Van de Vijver, B., Vochten, R., Geys, J., Verbruggen, C., Beyens, L. (1997) Mineralogical observations of weddellite from South Georgia, Subantarctica. Neues Jahrbuch für Mineralogie - Monatshefte, 1997 (5) 193-202 doi:10.1127/njmm/1997/1997/193
Conti, Claudia, Casati, Marco, Colombo, Chiara, Possenti, Elena, Realini, Marco, Gatta, G. Diego, Merlini, Marco, Brambilla, Luigi, Zerbi, Giuseppe (2015) Synthesis of calcium oxalate trihydrate: New data by vibrational spectroscopy and synchrotron X-ray diffraction. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 150. 721-730 doi:10.1016/j.saa.2015.06.009
Sturm (née Rosseeva), Elena V., Frank-Kamenetskaya, Olga, Vlasov, Dmitry, Zelenskaya, Marina, Sazanova, Katerina, Rusakov, Alexey, Kniep, Rüdiger (2015) Crystallization of calcium oxalate hydrates by interaction of calcite marble with fungusAspergillus niger. American Mineralogist, 100 (11) 2559-2565 doi:10.2138/am-2015-5104
Curetti, Nadia, Pastero, Linda, Bernasconi, Davide, Cotellucci, Andrea, Corazzari, Ingrid, Archetti, Maurizio, Pavese, Alessandro (2021) Thermal Stability of Calcium Oxalates from CO2 Sequestration for Storage Purposes: An In-Situ HT-XRPD and TGA Combined Study. Minerals, 12 (1) 53 doi:10.3390/min12010053
Localities for WeddelliteHide
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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.