Parakeldyshite Mineral Data

General Parakeldyshite Information

Chemical Formula:

Na2ZrSi2O7

Composition:

Molecular Weight = 305.37 gm

Sodium 15.06 % Na 20.30 % Na₂O

Zirconium 29.87 % Zr 40.35 % ZrO₂

Silicon 18.39 % Si 39.35 % SiO₂

Oxygen 36.68 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Na₂ZrSi₂O₇

Environment:

As masses in nepheline syenite pegmatites which cut a foyaite.

IMA Status:

Approved IMA 1975

Locality:

Mt. Takhtarvumchorr and elsewhere in the Khibiny massif, and on Mt. Alluaiv and elsewhere in the Lovozero massif, Kola Peninsula, Russia. Link to MinDat.org Location Data.

Name Origin:

Named from the Greek para, for near, and its relation to keldyshite.

Name Pronunciation:

Parakeldyshite + Pronunciation

Synonym:

ICSD 24866

PDF 39-209

Parakeldyshite Image

Images:

Parakeldyshite

Comments: White pearly crystalline parakeldyshite in rock.
Location: Lagendalen, Larvik, Vestfold, Norway. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Parakeldyshite Crystallography

Axial Ratios:

a:b:c =0.8201:1:1.3328

Cell Dimensions:

a = 5.419, b = 6.607, c = 8.806, Z = 2; alpha = 71.5°, beta = 87.15°, gamma = 85.63° V = 297.75 Den(Calc)= 3.41

Crystal System:

Triclinic - PinacoidalH-M Symbol ( 1) Space Group: P1

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

By Intensity(I/I_o): 3.963(1), 2.913(0.9), 4.179(0.8),

Crystal Structure:

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Voronkov A A , Shumyatskaya N G , Pyatenko Y A , Journal of Structural Chemistry , 11 (1970) p.866-867, Crystal structure of a new natural modification of Na2Zr[Si2O7], Locality: synthetic

Physical Properties of Parakeldyshite

Color:

Bluish white, White.

Density:

3.39

Diaphaneity:

Translucent

Hardness:

5.5-6 - Knife Blade-Orthoclase

Luminescence:

Fluorescent, Short UV=orange-white.

Luster:

Vitreous (Glassy)

Streak:

white

Optical Properties of Parakeldyshite

Gladstone-Dale:

CI meas= 0.007 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= 0.01 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2034,KPDmeas= 0.204,KC= 0.2056
Ncalc = 1.7

Optical Data:

Biaxial (-), a=1.67, b=1.692, g=1.713, bire=0.0430

Pleochroism (x):

colorless.

Pleochroism (y):

colorless.

Pleochroism (z):

colorless.

Calculated Properties of Parakeldyshite

Electron Density:

Bulk Density (Electron Density)=3.24 gm/cc
note: Specific Gravity of Parakeldyshite =3.39 gm/cc.

Fermion Index:

Fermion Index = 0.04
Boson Index = 0.96

Photoelectric:

PE_{Parakeldyshite}= 41.12 barns/electron
U=PE_{Parakeldyshite} x rElectron Density= 133.28 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Parakeldyshite is Not Radioactive

Parakeldyshite Classification

Dana Class:

55.02.02.03 (55)Sorosilicate Si2O7 Groups, Generally with No Additional Anions

(55.02)with cations in [6] coordination

(55.02.02)Keldyshite group

55.02.02.01 Keldyshite Na2-xHxZrSi2O7•n(H2O) P1 1

55.02.02.02 Khibinskite K2ZrSi2O7 B2/m 2/m

55.02.02.03 Parakeldyshite Na2ZrSi2O7 P1 1

Strunz Class:

09.BC.10 09 - SILICATES (Germanates)

09.B - Sorosilicates

09.BC -Si2O7 groups, without non-tetrahedral anions;

09.BC.10 Khibinskite K2ZrSi2O7 B2/m 2/m

09.BC.10 Keldyshite Na2-xHxZrSi2O7•n(H2O) P1 1

09.BC.10 Parakeldyshite Na2ZrSi2O7 P1 1

Other Parakeldyshite Information

References:

NAME( AntBidBlaNic2) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990;www.saint-hilaire.ca) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990)

See Also:

Links to other databases for Parakeldyshite :
1 - Alkali-Nuts(English)
2 - Alkali-Nuts(Francais)
3 - Am. Min. Crystal Structure Database
4 - Athena
5 - EUROmin Project
6 - Ecole des Mines de Paris
7 - GeoScienceWorld
8 - Google Images
9 - Google Scholar
10 - Handbook of Mineralogy (MinSocAm)
11 - Handbook of Mineralogy (UofA)
12 - MinDAT
13 - Mineralienatlas (Deutsch)
14 - Online Mineral Museum
15 - QUT Mineral Atlas
16 - Ruff.Info

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Print or Cut-and-Paste your Parakeldyshite Specimen Label here :

Parakeldyshite

Na2ZrSi2O7
Dana No: 55.02.02.03 Strunz No: 09.BC.10
Locality:

Notes: