Cavansite
A valid IMA mineral species
This page kindly sponsored in memory of Laszlo Z. Valachi
About Cavansite
Formula:
Ca(VO)Si4O10 · 4H2O
Colour:
Greenish-blue to blue
Lustre:
Vitreous
Hardness:
3 - 4
Specific Gravity:
2.21 - 2.31
Crystal System:
Orthorhombic
Name:
For the elements calcium, vanadium, and silicon in the composition.
Dimorph of:
Ishida et al. (2009) suggest that cavansite is a low-temperature form and pentagonite a high-temperature form. Conditions of formation of both dimorphs are discussed in Ottens et al. (2025).
To distinguish pentagonite and cavansite one can compare the two under light with a strong blue component, like halogen or sunlight. The pentagonite is a very pure blue and the cavansite is green in comparison. The teal colour of cavansite may not show up in photos but it is real. Please see: https://www.mindat.org/mesg-609416.html#609580
To distinguish pentagonite and cavansite one can compare the two under light with a strong blue component, like halogen or sunlight. The pentagonite is a very pure blue and the cavansite is green in comparison. The teal colour of cavansite may not show up in photos but it is real. Please see: https://www.mindat.org/mesg-609416.html#609580
Unique Identifiers
Mindat ID:
921
Long-form identifier:
mindat:1:1:921:0
IMA Classification of Cavansite
Approved
IMA Formula:
Ca(V4+O)(Si4O10) · 4H2O
Approval year:
1967
First published:
1967
Classification of Cavansite
9.EA.50
9 : SILICATES (Germanates)
E : Phyllosilicates
A : Single nets of tetrahedra with 4-, 5-, (6-), and 8-membered rings
9 : SILICATES (Germanates)
E : Phyllosilicates
A : Single nets of tetrahedra with 4-, 5-, (6-), and 8-membered rings
74.3.7.1
74 : PHYLLOSILICATES Modulated Layers
3 : Modulated Layers with joined strips
74 : PHYLLOSILICATES Modulated Layers
3 : Modulated Layers with joined strips
14.14.1
14 : Silicates not Containing Aluminum
14 : Silicates of V and Bi
14 : Silicates not Containing Aluminum
14 : Silicates of V and Bi
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 |
|---|---|---|
| Cav | 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 Cavansite
Vitreous
Transparency:
Transparent
Colour:
Greenish-blue to blue
Hardness:
3 - 4 on Mohs scale
Tenacity:
Brittle
Cleavage:
Distinct/Good
Good on {010}
Good on {010}
Density:
2.21 - 2.31 g/cm3 (Measured) 2.33 g/cm3 (Calculated)
Optical Data of Cavansite
Type:
Biaxial (+)
RI values:
nα = 1.542(2) nβ = 1.544(2) nγ = 1.551(2)
2V:
Measured: 52° , Calculated: 58°
Max. Birefringence:
δ = 0.009
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.
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.
Surface Relief:
Moderate
Dispersion:
r < v extreme. Dispersion opposite to that of pentagonite.
Optical Extinction:
Parallel. X = b; Y = a; Z = c.
Pleochroism:
Visible
Comments:
X=Z= colorless
Y= blue
Y= blue
Chemistry of Cavansite
Mindat Formula:
Ca(VO)Si4O10 · 4H2O
Element Weights:
Crystallography of Cavansite
Crystal System:
Orthorhombic
Class (H-M):
mmm (2/m 2/m 2/m) - Dipyramidal
Cell Parameters:
a = 9.792(2) Å, b = 13.644(3) Å, c = 9.629(2) Å
Ratio:
a:b:c = 0.718 : 1 : 0.706
Unit Cell V:
1,286.45 ų (Calculated from Unit Cell)
Z:
4
Morphology:
Prismatic crystals, spherulitic rosettes.
Twinning:
No twinning observed.
Comment:
Space group Pcnm.
Crystal Structure
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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) |
|---|---|---|---|---|---|---|---|
| 0000316 | Cavansite | Evans H T (1973) The crystal structures of cavansite and pentagonite American Mineralogist 58 412-424 |  | 1973 | 0 | 293 | |
| 0019718 | Cavansite | Danisi R M, Armbruster T, Lazic B (2012) In situ dehydration behavior of zeolite-like cavansite: A single-crystal X-ray study American Mineralogist 97 1874-1880 | 2012 | Wagholi quarry, Poona district, India | 0 | 293 | |
| 0019719 | Cavansite | Danisi R M, Armbruster T, Lazic B (2012) In situ dehydration behavior of zeolite-like cavansite: A single-crystal X-ray study American Mineralogist 97 1874-1880 | 2012 | Wagholi quarry, Poona district, India | 0 | 348 | |
| 0019720 | Cavansite | Danisi R M, Armbruster T, Lazic B (2012) In situ dehydration behavior of zeolite-like cavansite: A single-crystal X-ray study American Mineralogist 97 1874-1880 | 2012 | Wagholi quarry, Poona district, India | 0 | 448 | |
| 0019721 | Cavansite | Danisi R M, Armbruster T, Lazic B (2012) In situ dehydration behavior of zeolite-like cavansite: A single-crystal X-ray study American Mineralogist 97 1874-1880 | 2012 | Wagholi quarry, Poona district, India | 0 | 623 | |
| 0018620 | Cavansite | Hughes J M, Derr R S, Cureton F, Campana C F, Druschel G (2011) The crystal structure of cavansite: location of the H2O molecules and hydrogen atoms in Ca(VO)(Si4O10)*4H2O The Canadian Mineralogist 49 1267-1272 | 2011 | Pune, India | 0 | 100 | |
| 0018621 | Cavansite | Hughes J M, Derr R S, Cureton F, Campana C F, Druschel G (2011) The crystal structure of cavansite: location of the H2O molecules and hydrogen atoms in Ca(VO)(Si4O10)*4H2O The Canadian Mineralogist 49 1267-1272 | 2011 | Pune, India | 0 | 293 | |
| 0019264 | Cavansite | Ishida N, Kimata M, Nishida N, Hatta T, Shimizu M, Akasaka T (2009) Polymorphic relation between cavanite and pentagonite: genetic implications of oxonium ion in cavansite Journal of Mineralogical and Petrological Sciences 104 241-252 | 2009 | Deccan basalts, Wagholi, India | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Loading XRD data...
Data courtesy of RRUFF project at University of Arizona, used with permission.
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 7.964 Å | (100) |
| 6.854 Å | (50) |
| 6.132 Å | (25) |
| 3.930 Å | (25) |
| 3.420 Å | (25) |
| 2.779 Å | (25) |
| 4.531 Å | (13) |
Comments:
Owyhee Dam, Oregon, USA. Data from the type description.
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 3a: Earth’s earliest Hadean crust | >4.50 |
| 10 : Basalt-hosted zeolite minerals | |
| Stage 3b: Earth’s earliest hydrosphere | >4.45 |
| 16 : Low-? aqueous alteration of Hadean subaerial lithologies (see also #23) | |
| Near-surface Processes | |
| 23 : Subaerial aqueous alteration by non-redox-sensitive fluids (see also #47) |
Geological Setting:
Basalt vesicular filling.
Type Occurrence of Cavansite
General Appearance of Type Material:
Blue radiating clusters up to 25 mm in diameter and as single crystals up to 0.2 mm long.
Place of Conservation of Type Material:
National Museum of Natural History (Smithsonian), Washington, D.C., USA, 120583, 120584, 122769.
Geological Setting of Type Material:
In brown tuff of late Miocene age and in basalt and breccia of Eocene age.
Associated Minerals at Type Locality:
Synonyms of Cavansite
Other Language Names for Cavansite
Common Associates
Associated Minerals Based on Photo Data:
| 532 photos of Cavansite associated with Stilbite-Ca | NaCa4(Si27Al9)O72 · 28H2O |
| 313 photos of Cavansite associated with Stilbite Subgroup | M6-7[Al8-9Si27-28O72] · nH2O |
| 156 photos of Cavansite associated with Calcite | CaCO3 |
| 138 photos of Cavansite associated with Heulandite Subgroup | (Na/Ca/K)5-6[Al8-9 Si27-28 O72] · nH2O |
| 71 photos of Cavansite associated with Mordenite | (Na2,Ca,K2)4(Al8Si40)O96 · 28H2O |
| 20 photos of Cavansite associated with Pentagonite | Ca(VO)Si4O10 · 4H2O |
| 20 photos of Cavansite associated with Okenite | Ca10Si18O46 · 18H2O |
| 19 photos of Cavansite associated with Heulandite-Ca | (Ca,Na)5(Si27Al9)O72 · 26H2O |
| 15 photos of Cavansite associated with Quartz | SiO2 |
| 12 photos of Cavansite associated with Chabazite-Ca | (Ca,K2,Na2)2[Al2Si4O12]2 · 12H2O |
Related Minerals - Strunz-mindat Grouping
| 9.EA. | Hydroxymcglassonite-(K) | KSr4Si8O20(OH) · 8H2O |
| 9.EA. | Miyawakiite-(Y) | ◻Y4Fe2(Si8O20)(CO3)4(H2O)3 |
| 9.EA. | Bussyite-(Y) | (Y,REE,Ca)3(Na,Ca)6MnSi9Be5(O,OH,F)34 |
| 9.EA. | Fluorapophyllite-(NH4) | NH4Ca4(Si8O20)F · 8H2O |
| 9.EA.05 | Gillespite | BaFe2+Si4O10 |
| 9.EA.05 | Cuprorivaite | CaCuSi4O10 |
| 9.EA.05 | Wesselsite | SrCuSi4O10 |
| 9.EA.05 | Effenbergerite | BaCuSi4O10 |
| 9.EA.07 | Fluorapophyllite-(Cs) | CsCa4(Si8O20)F · 8H2O |
| 9.EA.10 | Ekanite | Ca2ThSi8O20 |
| 9.EA.15 | Fluorapophyllite-(Na) | NaCa4(Si8O20)F · 8H2O |
| 9.EA.15 | Fluorapophyllite-(K) | KCa4(Si8O20)(F,OH) · 8H2O |
| 9.EA.15 | Hydroxyapophyllite-(K) | KCa4(Si8O20)(OH,F) · 8H2O |
| 9.EA.20 | Magadiite | Na2Si14O29 · 11H2O |
| 9.EA.25 | Dalyite | K2ZrSi6O15 |
| 9.EA.25 | Davanite | K2TiSi6O15 |
| 9.EA.30 | Sazhinite-(La) | Na3La[Si6O15] · 2H2O |
| 9.EA.30 | Sazhinite-(Ce) | Na3CeSi6O15 · 2H2O |
| 9.EA.35 | Armstrongite | CaZr[Si6O15] · 3H2O |
| 9.EA.40 | Okenite | Ca10Si18O46 · 18H2O |
| 9.EA.45 | Perettiite-(Y) | Y2Mn4FeSi2B8O24 |
| 9.EA.45 | Nekoite | Ca3Si6O15 · 7H2O |
| 9.EA.45 | Badakhshanite-(Y) | Y2Mn4Al(Si2B7BeO24) |
| 9.EA.47 | Shlykovite | KCa[Si4O9(OH)] · 3H2O |
| 9.EA.50 | Diegogattaite | Na2CaCu2Si8O20 · H2O |
| 9.EA.52 | Yangite | PbMnSi3O8 · H2O |
| 9.EA.55 | Pentagonite | Ca(VO)Si4O10 · 4H2O |
| 9.EA.60 | Penkvilksite | Na4Ti2Si8O22 · 4H2O |
| 9.EA.60 | Tumchaite | Na2Zr(Si4O11) · 2H2O |
| 9.EA.65 | Nabesite | Na2BeSi4O10 · 4H2O |
| 9.EA.70 | Ajoite | (K,Na)Cu7AlSi9O24(OH)6 · 3H2O |
| 9.EA.75 | Zeravshanite | Na2Cs4Zr3[Si18O45]*2H2O |
| 9.EA.80 | Bussyite-(Ce) | (Ce,REE)3(Na,H2O)6MnSi9Be5(O,OH)30F4 |
| 9.EA.85 | Plumbophyllite | Pb2Si4O10 · H2O |
Other Information
Notes:
Soluble with difficulty in acids. In HNO3 the blue color bleaches out and turns olive brown. When heated on a microscope slide in H2SO4, a fine white crystalline precipitate is slowly formed.
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 Cavansite
mindat.org URL:
https://www.mindat.org/min-921.html
Please feel free to link to this page.
Please feel free to link to this page.
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References for Cavansite
Reference List:
Staples, Lloyd W., Evans, Howard T., Lindsay, and James R. (1973) Cavansite and pentagonite, new dimorphous calcium vanadium silicate minerals from Oregon. American Mineralogist, 58 (5-6) 405-411
Evans, Howard T., Jr. (1973) The crystal structures of cavansite and pentagonite. American Mineralogist, 58 (5-6) 412-424
Powar, K.B., Byrappa, Kullaiah (2001) X-ray, thermal and infrared studies of cavansite from Wagholi western Maharashtra, India. Journal of Mineralogical and Petrological Sciences, 96 (1) 1-6 doi:10.2465/jmps.96.1
White, John (2002) Let's Get It Right: Cavansite or Pentagonite? Rocks & Minerals, 77 (4). 274-275 doi:10.1080/00357529.2002.9925646
Prasad, P.S.R., Prasad, K. Shiva (2007) Dehydration behavior of natural cavansite: An in-situ FTIR and Raman spectroscopic study. Materials Chemistry and Physics, 105. 395-400 doi:10.1016/j.matchemphys.2007.05.005
Ishida, Naoya, Kimata, Mitsuyoshi, Nishida, Norimasa, Hatta, Tamao, Shimizu, Masahiro, Akasaka, Takeshi (2009) Polymorphic relation between cavansite and pentagonite: Genetic implications of oxonium ion in cavansite. Journal of Mineralogical and Petrological Sciences, 104 (4) 241-252 doi:10.2465/jmps.070724b
Hughes, John M., Derr, Rebecca S., Cureton, Forrest, Campana, Charles F., Druschel, Gregory (2011) The crystal structure of cavansite: location of the H2O molecules and hydrogen atoms in Ca(VO)(Si4O10)·4H2O. The Canadian Mineralogist, 49 (5) 1267-1272 doi:10.3749/canmin.49.5.1267
Danisi, R. M., Armbruster, T., Lazic, B. (2012) In situ dehydration behavior of zeolite-like cavansite: A single-crystal X-ray study. American Mineralogist, 97 (11) 1874-1880 doi:10.2138/am.2012.4228
Frost, Ray L., Xi, Yunfei (2012) Vibrational spectroscopic study of the minerals cavansite and pentagonite Ca(V4+O)Si4O10·4H2O. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 95. 263-269 doi:10.1016/j.saa.2012.04.021
Localities for Cavansite
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.
Brazil | |
| Lapis 29 (9) |
Iceland | |
India | |
| Praszkier et al. (2007) +1 other reference |
| Praszkier (2009) |
| Ottens et al. (2019) | |
| Praszkier et al. (2007) |
| Praszkier (2009) | |
| Betts (n.d.) +1 other reference | |
| www.hedegaard.com (n.d.) | |
| King (1989) | |
| - (n.d.) | |
| Praszkier et al. (2007) | |
| Praszkier et al. (2007) |
New Zealand | |
| Lapis 29 (9) +1 other reference |
USA | |
| Rocks & Minerals: 64 (5) +1 other reference |
| Wieting (1995) | |
| Staples et al. (1967) +1 other reference |
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Wagholi Quarries, Wagholi, Pune District, Pune Division, Maharashtra, India