Cavansite Mineral Data

Cavansite Mineral Data +

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General Cavansite Information

Chemical Formula:

Ca(VO)Si4O10·4(H2O)

Composition:

Molecular Weight = 451.42 gm

Calcium 8.88 % Ca 12.42 % CaO

Vanadium 11.28 % V 20.15 % V₂O₅

Silicon 24.89 % Si 53.24 % SiO₂

Hydrogen 1.79 % H 15.96 % H₂O

Oxygen 53.16 % O

______ ______

100.00 % 101.77 % = TOTAL OXIDE

Empirical Formula:

CaV⁵⁺Si₄O₁₁·4(H₂O)

Environment:

Secondary mineralization in basalts and andesites.

IMA Status:

Approved IMA 1973

Locality:

Deccan trap basalts, Poona, India. Link to MinDat.org Location Data.

Name Origin:

Named after its composition of calcium, vanadium, and silicon.

Synonym:

ICSD 1906

PDF 25-182

Cavansite Image

Images:

Cavansite

Comments: Brilliant blue balls of acicular crystals of cavansite to 1 cm in size richly scattered about a matrix of colorless stilbite crystals.
Location: Wagholi, Poona district, Maharashtra, India. Scale: 7.5 x 9 x 8 cm.
© Dan Weinrich

Cavansite Crystallography

Axial Ratios:

a:b:c =0.7148:1:0.7019

Cell Dimensions:

a = 9.778, b = 13.678, c = 9.601, Z = 4; V = 1,284.07 Den(Calc)= 2.33

Crystal System:

Orthorhombic - DipyramidalH-M Symbol (2/m 2/m 2/m) Space Group: Pcmn

$Help on X Ray Diffraction:$ X Ray Diffraction:

By Intensity(I/I_o): 7.964(1), 6.854(0.5), 6.132(0.25),

Forms:

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Forms: [ 1 0 1] [ 1 1 0]

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Crystal Structure:

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Evans H T , American Mineralogist , 58 (1973) p.412-424, The crystal structures of cavansite and pentagonite

Physical Properties of Cavansite

Cleavage:

[010] Good

Color:

Greenish blue, Dark blue.

Density:

2.21 - 2.31, Average = 2.25

Diaphaniety:

Subtransparent

Fracture:

Brittle - Generally displayed by glasses and most non-metallic minerals.

Hardness:

3-4 - Calcite-Fluorite

Luster:

Vitreous (Glassy)

Streak:

bluish white

Optical Properties of Cavansite

Gladstone-Dale:

CI meas= 0.07 (Fair) - where the CI = (1-KPDmeas/KC)
CI calc= 0.098 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2342,KPDmeas= 0.2414,KC= 0.2596

Optical Data:

Biaxial (+), a=1.542, b=1.544, g=1.551, bire=0.0090, 2V(Calc)=58, 2V(Meas)=52.

Calculated Properties of Cavansite

Electron Density:

r_electron=2.27 gm/cc
note: r_Cavansite=2.26 gm/cc.

Fermion Index

Fermion Index = 0.01228
Boson Index = 0.98772

Photoelectric:

PE_Cavansite= 4.15 barns/electron
U=PE_Cavansite x r_electron= 9.42 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Cavansite is Not Radioactive

Cavansite Classification

Dana Class:

74.3.7.1 (74)Phyllosilicate Modulated Layers

(74.3)with joined strips

(74.3.7)V phyllosilicates

74.3.7.1 Cavansite Ca(VO)Si4O10·4(H2O) Pcmn 2/m 2/m 2/m

74.3.7.2 Pentagonite Ca(VO)Si4O10·4(H2O) Ccm21 mm2

Strunz Class:

VIII/H.36-10 VIII - Silicates

VIII/H - Phyllosilicates (layered) Mica minerals with other simple layers, [Si6O15]6- and others

VIII/H.36 - Cavansite - Pentagonite series

VIII/H.36-10 Cavansite Ca(VO)Si4O10·4(H2O) Pcmn 2/m 2/m 2/m

VIII/H.36-20 Pentagonite Ca(VO)Si4O10·4(H2O) Ccm21 mm2

Other Cavansite Information

References:

NAME( MinRec) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990)

See Also:

Links to other databases for Cavansite :
1 - Am. Min. Crystal Structure Database
2 - Amethyst Galleries' Mineral Gallery
3 - Athena
4 - CalTech Mineral Spectroscopy
5 - EUROmin Project
6 - Ecole des Mines de Paris
7 - Google Images
8 - Google Scholar
9 - Handbook of Mineralogy (MinSocAm)
10 - Handbook of Mineralogy (UofA)
11 - HyperPhysics
12 - MinDAT
13 - MinMax(Deutsch)
14 - MinMax(English)
15 - Mineralienatlas (Deutsch)
16 - QUT Mineral Atlas
17 - Ruff.Info
18 - WWW-MINCRYST

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Cavansite

Ca(VO)Si4O10·4(H2O)
Dana No: 74.3.7.1 Strunz No: VIII/H.36-10
Locality:

Notes: