Caoxite
A valid IMA mineral species
This page is currently not sponsored. Click here to sponsor this page.
About Caoxite
Formula:
Ca(C2O4) · 3H2O
Colour:
Colorless
Lustre:
Vitreous
Hardness:
2 - 2½
Specific Gravity:
1.87 (Calculated)
Crystal System:
Triclinic
Name:
For the acronym of "Centennial Anniversary Of X-rays" and also for Calcium Oxalate.
This page provides mineralogical data about Caoxite.
Unique Identifiers
Mindat ID:
6845
Long-form identifier:
mindat:1:1:6845:7
Similar Names
| Guixite | Valid as an unnamed mineral | Cu2(AsO4,SiO4)(OH,H2O) · H2O (?) |
IMA Classification of Caoxite
Approved
IMA Formula:
Ca(C2)6+O4·3H2O
Approval year:
1996
First published:
1997
Classification of Caoxite
10.AB.50
10 : ORGANIC COMPOUNDS
A : Salts of organic acids
B : Oxalates
10 : ORGANIC COMPOUNDS
A : Salts of organic acids
B : Oxalates
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 |
|---|---|---|
| Cao | 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 Caoxite
Vitreous
Transparency:
Transparent
Colour:
Colorless
Streak:
White
Hardness:
2 - 2½ on Mohs scale
Tenacity:
Brittle
Cleavage:
Distinct/Good
{010}
{010}
Fracture:
Irregular/Uneven
Density:
1.87 g/cm3 (Calculated)
Optical Data of Caoxite
Type:
Biaxial (-)
RI values:
nα = 1.483(3) nβ = 1.516 nγ = 1.533(3)
2V:
Measured: 70° (2)
Max. Birefringence:
δ = 0.050
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:
Low (negative)
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.
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.
Dispersion:
relatively strong
Chemistry of Caoxite
Mindat Formula:
Ca(C2O4) · 3H2O
Element Weights:
Elements listed:
Crystallography of Caoxite
Crystal System:
Triclinic
Class (H-M):
1 - Pinacoidal
Space Group:
P1
Cell Parameters:
a = 6.097(1) Å, b = 7.145(1) Å, c = 8.434(1) Å
α = 76.54(1)°, β = 70.30(1)°, γ = 70.75(1)°
α = 76.54(1)°, β = 70.30(1)°, γ = 70.75(1)°
Ratio:
a:b:c = 0.853 : 1 : 1.18
Unit Cell V:
323.49 ų (Calculated from Unit Cell)
Z:
2
Crystal Structure
Load
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
Show
Big Balls | Small Balls | Just Balls | Spacefill
Polyhedra Off | Si Polyhedra | All Polyhedra
Remove metal-metal sticks
Big Balls | Small Balls | Just Balls | Spacefill
Polyhedra Off | Si Polyhedra | All Polyhedra
Remove metal-metal sticks
Display Options
Black Background | White Background
Perspective On | Perspective Off
2D | Stereo | Red-Blue | Red-Cyan
Black Background | White Background
Perspective On | Perspective Off
2D | Stereo | Red-Blue | Red-Cyan
View
CIF File Best | x | y | z | a | b | c
CIF File Best | x | y | z | a | b | c
Rotation
Stop | Start
Stop | Start
Labels
Console Off | On | Grey | Yellow
Console Off | On | Grey | Yellow
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) |
|---|---|---|---|---|---|---|---|
| 0014895 | Caoxite | Basso R, Lucchetti G, Zefiro L, Palenzona A (1997) Caoxite, Ca(H2O)3(C2O4), a new mineral from the Cerchiara mine, northern Apennines, Italy Neues Jahrbuch fur Mineralogie, Monatshefte 1997 84-96 | 1997 | Cerchiara mine, Val di Vara, northern Apennines, Italy | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 7.92 Å | (m) |
| 5.26 Å | (m) |
| 5.52 Å | (vs) |
| 4.99 Å | (m) |
| 3.643 Å | (m) |
| 2.834 Å | (s) |
| 2.758 Å | (m) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 10a: Neoproterozoic oxygenation/terrestrial biosphere | <0.6 |
| 53 : Other minerals with taphonomic origins | <0.4 |
Type Occurrence of Caoxite
General Appearance of Type Material:
spherulitic and isolated aggregates, up to 0.5 mm across, consisting of colorless, stocky
crystals
crystals
Place of Conservation of Type Material:
Sezione di Mineralogia, Dipartimento di Scienze della Terra, Universita di Genova, Italy.
Geological Setting of Type Material:
veinlets cutting metamorphosed Mn–Ba-rich cherts in an obducted ophiolite.
Associated Minerals at Type Locality:
Synonyms of Caoxite
Other Language Names for Caoxite
Related Minerals - Strunz-mindat Grouping
| 10.AB. | Deveroite-(Ce) | Ce2(C2O4)3 · 10H2O |
| 10.AB. | Edwindavisite | Cu(C2O4)(NH3) |
| 10.AB.X | Falottaite | MnC2O4 · 3H2O |
| 10.AB. | Uroxite | [(UO2)2(C2O4)(OH)2(H2O)2] · H2O |
| 10.AB.05 | Katsarosite | Zn(C2O4) · 2H2O |
| 10.AB.05 | Andreybulakhite | Ni(C2O4) · 2H2O |
| 10.AB.05 | Humboldtine | Fe2+(C2O4) · 2H2O |
| 10.AB.05 | Lindbergite | Mn2+(C2O4) · 2H2O |
| 10.AB.10 | Glushinskite | Mg(C2O4) · 2H2O |
| 10.AB.15 | Moolooite | Cu(C2O4) · nH2O |
| 10.AB.20 | Stepanovite | NaMgFe3+(C2O4)3 · 8-9H2O |
| 10.AB.25 | Minguzzite | K3Fe3+(C2O4)3 · 3H2O |
| 10.AB.30 | Wheatleyite | Na2Cu(C2O4)2 · 2H2O |
| 10.AB.35 | Zhemchuzhnikovite | NaMgAl(C2O4)3 · 8H2O |
| 10.AB.40 | Weddellite | Ca(C2O4) · (2.5-x)H2O |
| 10.AB.45 | Whewellite | Ca(C2O4) · H2O |
| 10.AB.47 | Fiemmeite | Cu2(C2O4)(OH)2 · 2H2O |
| 10.AB.50 | Middlebackite | Cu2C2O4(OH)2 |
| 10.AB.52 | Metauroxite | (UO2)2(C2O4)(OH)2(H2O)2 |
| 10.AB.55 | Oxammite | (NH4)2(C2O4) · H2O |
| 10.AB.60 | Natroxalate | Na2(C2O4) |
| 10.AB.60 | Phoxite | (NH4)2Mg2(C2O4)(PO3OH)2(H2O)4 |
| 10.AB.60 | Carboferriphoxite | [(NH4)K(H2CO3)][Fe3+(HPO4)(H2PO4)(C2O4)] |
| 10.AB.60 | Ferriphoxite | [(NH4)2K(H2O)][Fe3+(HPO4)2(C2O4)] |
| 10.AB.65 | Coskrenite-(Ce) | Ce2(SO4)2(C2O4) · 8H2O |
| 10.AB.70 | Levinsonite-(Y) | (Y,Nd,La)Al(C2O4)(SO4)2 · 12H2O |
| 10.AB.75 | Zugshunstite-(Ce) | (Ce,Nd,La)Al(C2O4)(SO4)2 · 12H2O |
| 10.AB.80 | Novgorodovaite | Ca2(C2O4)Cl2 · 2H2O |
Fluorescence of Caoxite
None observed
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 Caoxite
mindat.org URL:
https://www.mindat.org/min-6845.html
Please feel free to link to this page.
Please feel free to link to this page.
Search Engines:
External Links:
Mineral Dealers:
References for Caoxite
Reference List:
Basso, R., Lucchetti, G., Zefiro, L., Palenzona, A. (1997) Caoxite, Ca(H2O)3(C2O4), a new mineral from the Cerchiara mine, northern Apennines, Italy. Neues Jahrbuch für Mineralogie - Monatshefte, 1997 (2) 84-96 doi:10.1127/njmm/1997/1997/84
Jambor, John L., Grew, Edward S., Roberts, Andrew C. (1998) New mineral names. American Mineralogist, 83 (1) 185-189
Echigo, T., Kimata, M., Kyono, A., Shimizu, M., Hatta, T. (2005) Re-investigation of the crystal structure of whewellite [Ca(C2O4)·H2O] and the dehydration mechanism of caoxite [Ca(C2O4)·3H2O]. Mineralogical Magazine, 69 (1) 77-88 doi:10.1180/0026461056910235
Piilonen, P. C. (2005) New Mineral Names. American Mineralogist, 90 (8) 1466-1469 doi:10.2138/am.2005.448
Localities for Caoxite
Showing 1 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.
Italy (TL) | |
| Basso et al. (1997) +1 other reference |
Quick NavTopAbout CaoxiteUnique IdentifiersSimilar NamesIMA Classification Classification Mineral SymbolsPhysical Properties Optical Data Chemistry Crystallography Crystal StructureX-Ray Powder DiffractionGeological EnvironmentType Occurrence SynonymsOther LanguagesStrunz-MindatFluorescence Other InformationInternet Links References Localities Locality List
Cerchiara Mine, Borghetto di Vara, La Spezia Province, Liguria, Italy