Penkvilksite Mineral Data

Penkvilksite Mineral Data +

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General Penkvilksite Information

Chemical Formula:

Na4(Ti++++,Zr)2[Si8O22]·4(H2O)

Composition:

Molecular Weight = 858.12 gm

Sodium 10.72 % Na 14.45 % Na₂O

Zirconium 5.32 % Zr 7.18 % ZrO₂

Titanium 8.37 % Ti 13.96 % TiO₂

Silicon 26.18 % Si 56.01 % SiO₂

Hydrogen 0.94 % H 8.40 % H₂O

Oxygen 48.48 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Na₄Ti_1.5Zr_0.5Si₈O₂₂·4(H₂O)

IMA Status:

Approved IMA 1974

Locality:

Jubilee pegmatite deposit, Mt. Karnarsut, Lovozero massif, Kola peninsula, Russia. Link to MinDat.org Location Data.

Name Origin:

Named from the Lapp "penk" and "vilkis", white and curly in allusion to its appearance.

Penkvilksite Image

Images:

Penkvilksite

Comments: Massive white cluster of Penkvilksite.
Location: Lovozero, Kola Peninsula, Russia. Scale: .5 x 2.5 cm.
© John Veevaert

Penkvilksite Crystallography

Axial Ratios:

a:b:c =1.0262:1:0.8464

Cell Dimensions:

a = 8.956, b = 8.727, c = 7.387, Z = 1; beta = 112.74° V = 532.48 Den(Calc)= 2.68

Crystal System:

Monoclinic - PrismaticH-M Symbol (2/m) Space Group: P 2₁/c

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

By Intensity(I/I_o): 8.29(1), 3.339(0.9), 2.884(0.8),

Crystal Structure:

Mouse
drag1 - LMB Manipulate Structure
drag2 - RMB Resize/Rotate
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Help on Above

Merlino S , Pasero M , Artioli G , Khomyakov A P , American Mineralogist , 79 (1994) p.1185-1193, Penkvilksite, a new kind of silicate structure: OD character, X-ray, single-crystal (1M), and powder Rietveld (2O) refinements of two MDO polytypes, Sample 2O

View Additional jPOWD Structure files for Penkvilksite
[1]

Physical Properties of Penkvilksite

Cleavage:

[???] Perfect

Color:

Colorless, White.

Density:

2.63

Diaphaniety:

Transparent

Habit:

Porcelainous - Fine-grained, translucent massive material like broken china

Hardness:

5 - Apatite

Luster:

Pearly

Streak:

white

Optical Properties of Penkvilksite

Gladstone-Dale:

CI meas= -0.025 (Excellent) - where the CI = (1-KPDmeas/KC)
CI calc= -0.006 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2439,KPDmeas= 0.2485,KC= 0.2425

Optical Data:

Biaxial (+), a=1.64, b=1.646, g=1.675, bire=0.0350, 2V(Calc)=50, 2V(Meas)=50.

Calculated Properties of Penkvilksite

Electron Density:

r_electron=2.65 gm/cc
note: r_Penkvilksite=2.68 gm/cc.

Fermion Index

Fermion Index = 0.02924
Boson Index = 0.97076

Photoelectric:

PE_Penkvilksite= 9.45 barns/electron
U=PE_Penkvilksite x r_electron= 25.09 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Penkvilksite is Not Radioactive

Penkvilksite Classification

Dana Class:

70.2.2.1 (70)Inosilicate Column or Tube Structures

(70.2)with Si2O7 dimers

(70.2.2)Dana Group

70.2.2.1 Penkvilksite Na4(Ti,Zr)2[Si8O22]·4(H2O) P 2₁/c 2/m

70.2.2.2 Tumchaite! Na2(Zr,Sn)Si4O11·2(H2O) P 2₁/c 2/m

Strunz Class:

VIII/F.34-30 VIII - Silicates

VIII/F - Inosilicates (chain and band) complex chain structure. Cylindric chains and others

VIII/F.34 - Grumantite - Penkvilksite series

VIII/F.34-10 Narsarsukite Na2(Ti,Fe)Si4(O,F)11 I 4/m 4/m

VIII/F.34-20 Vlasovite Na2ZrSi4O11 C 2/c 2/m

VIII/F.34-30 Penkvilksite Na4(Ti,Zr)2[Si8O22]·4(H2O) P 2₁/c 2/m

VIII/F.34-40 Tumchaite! Na2(Zr,Sn)Si4O11·2(H2O) P 2₁/c 2/m

Other Penkvilksite Information

References:

NAME( Dana8) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990)

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Penkvilksite

Na4(Ti++++,Zr)2[Si8O22]·4(H2O)
Dana No: 70.2.2.1 Strunz No: VIII/F.34-30
Locality:

Notes: