Mineralogy Database

Pentagonite Mineral Data

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General Pentagonite Information

Help on Chemical  Formula: Chemical Formula: Ca(VO)Si4O10•4(H2O)
Help on Composition: 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
Help on Empirical Formula: Empirical Formula: CaV5+Si4O11•4(H2O)
Help on Environment: Environment: Alteration product occurring in basalts and tuffs.
Help on IMA Status: IMA Status: Approved IMA 1973
Help on Locality: Locality: Lake Owyhee State Park, Malheur County, and Goble, Columbia County, Oregon, USA. Link to MinDat.org Location Data.
Help on Name Origin: Name Origin: Named from the Greek, penta, "five" and angle in allusion to the fiveling twins common in this species.
Help on Name Pronunciation: Name Pronunciation: Pentagonite + Pronunciation Say PENTAGONITE
Help on Synonym: Synonym: ICSD 10262
  PDF 25-181

Pentagonite Image

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Comments: Blue, crystalline aggregate of pentagonite on zeolite.
Location: Wagholi quarries, Poona, India. Scale: Grain size 1.2 cm.
© Tom Loomis / Dakota Matrix

Pentagonite Crystallography

Help on Axial Ratios: Axial Ratios: a:b:c =0.7356:1:0.635
Help on Cell Dimensions: Cell Dimensions: a = 10.298, b = 13.999, c = 8.89, Z = 4; V = 1,281.60 Den(Calc)= 2.34
Help on Crystal System: Crystal System: Orthorhombic - Pyramidal H-M Symbol (mm2) Space Group: Ccm21
Help on X Ray Diffraction: X Ray Diffraction: By Intensity(I/Io): 3.755(1), 3.92(1), 6.071(1),
Help on Forms: Forms:

Dbl Clk - Start-Stop Rotation
RMB - Cycle Display Modes
Drag1 - Manipulate Crystal
Drag2 - Resize

S - Stereo
I - Indicies
<space> - Start-Stop Rotation
F - Fit to Screen
M - Menu

Help on Above

Forms: ( 2 0 1) ( 1 1 0) ( 0 0 1)

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Physical Properties of Pentagonite

Help on Cleavage: Cleavage: {010} Good
Help on Color: Color: Greenish blue.
Help on Density: Density: 2.33
Help on Diaphaneity: Diaphaneity: Transparent
Help on Fracture: Fracture: Brittle - Generally displayed by glasses and most non-metallic minerals.
Help on Habit: Habit: Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline).
Help on Habit: Habit: Rosette - Bundled tabular aggregates resembling rose flower petals.
Help on Habit: Habit: Twinning Common - Crystals are usually twinned.
Help on Hardness: Hardness: 3-4 - Calcite-Fluorite
Help on Luster: Luster: Vitreous (Glassy)
Help on Streak: Streak: bluish white

Optical Properties of Pentagonite

Help on Gladstone-Dale: Gladstone-Dale: CI meas= 0.102 (Poor) - where the CI = (1-KPDmeas/KC)
CI calc= 0.106 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2321,KPDmeas= 0.2331,KC= 0.2596
Ncalc = 1.6 - 1.61
Help on Optical Data: Optical Data: Biaxial (-), a=1.533-1.54, b=1.544-1.545, g=1.547-1.55, bire=0.0100-0.0140, 2V(Calc)=54-88, 2V(Meas)=50. Dispersion r < v extreme.
Help on Pleochroism (x): Pleochroism (x): colorless.
Help on Pleochroism (y): Pleochroism (y): blue.
Help on Pleochroism (z): Pleochroism (z): colorless.

Calculated Properties of Pentagonite

Help on Electron Density: Electron Density: Bulk Density (Electron Density)=2.34 gm/cc
note: Specific Gravity of Pentagonite =2.33 gm/cc.
Help on Fermion Index: Fermion Index: Fermion Index = 0.01
Boson Index = 0.99
Help on Photoelectric: Photoelectric: PEPentagonite = 4.15 barns/electron
U=PEPentagonite x rElectron Density= 9.71 barns/cc.
Help on Radioactivity: Radioactivity: GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Pentagonite is Not Radioactive

Pentagonite Classification

Help on  Dana Class: Dana Class: (74)Phyllosilicate Modulated Layers
  (74.03)with joined strips
  (74.03.07)V phyllosilicates Cavansite Ca(VO)Si4O10•4(H2O) Pcmn 2/m 2/m 2/m Pentagonite Ca(VO)Si4O10•4(H2O) Ccm21 mm2
Help on  Strunz Class: Strunz Class: 09.EA.55 09 - SILICATES (Germanates)
  09.E - Phyllosilicates
  09.EA -Single nets of tetrahedra with 4-, 5-, (6-), and 8-membered rings
09.EA.55 Pentagonite Ca(VO)Si4O10•4(H2O) Ccm21 mm2

Other Pentagonite Information

Help on References: References: NAME( Dana8) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Dana8)
Help on See Also: See Also: Links to other databases for Pentagonite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - EUROmin Project
4 - Ecole des Mines de Paris
5 - GeoScienceWorld
6 - Google Images
7 - Google Scholar
8 - Handbook of Mineralogy (MinSocAm)
9 - Handbook of Mineralogy (UofA)
10 - MinDAT
11 - Mineralienatlas (Deutsch)
12 - Online Mineral Museum
13 - QUT Mineral Atlas
14 - Ruff.Info

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Dana No: Strunz No: 09.EA.55





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