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:
CaV4+OSi4O10·4H2O
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 for Standard |
|---|---|---|
| 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. 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:
None to Very Low
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:
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/m2/m2/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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CIF File Best | x | y | z | a | b | c
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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) |
|---|---|---|---|---|---|---|---|
| 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 | |
| 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 | |
| 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 | |
| 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 | |
| 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 | |
| 0000316 | Cavansite | Evans H T (1973) The crystal structures of cavansite and pentagonite American Mineralogist 58 412-424 |  | 1973 | 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
Associations Based on Photo Data:
| 546 photos of Cavansite associated with Stilbite-Ca | NaCa4(Si27Al9)O72 · 28H2O |
| 314 photos of Cavansite associated with Stilbite Subgroup | M6-7[Al8-9Si27-28O72] · nH2O |
| 160 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 |
| 23 photos of Cavansite associated with Heulandite-Ca | (Ca,Na)5(Si27Al9)O72 · 26H2O |
| 21 photos of Cavansite associated with Okenite | Ca10Si18O46 · 18H2O |
| 20 photos of Cavansite associated with Pentagonite | Ca(VO)Si4O10 · 4H2O |
| 15 photos of Cavansite associated with Quartz | SiO2 |
| 13 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
Showing 17 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.
Brazil | |
| Frank et al. (2004) |
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 | |
| Frank et al. (2004) +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