Keldyshite Mineral Data

General Keldyshite Information

Chemical Formula:

Na2-xHxZrSi2O7•n(H2O)

Composition:

Molecular Weight = 330.41 gm

Sodium 10.44 % Na 14.07 % Na₂O

Zirconium 27.61 % Zr 37.29 % ZrO₂

Silicon 17.00 % Si 36.37 % SiO₂

Hydrogen 1.37 % H 12.27 % H₂O

Oxygen 43.58 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Na_1.5H_0.5ZrSi₂O₇•2(H₂O)

Environment:

A primary mineral in foyaites composed of partly albitized microcline, nepheline, sodalite, aegirine, and alkali amphibole, in a di®erentiated alkalic massif.

IMA Status:

Approved IMA 1962

Locality:

Tavaiok and Angoundasiok Rivers and on Mt. Alluaiv, Lovozero massif, and at Tachtarvumchorr, Khibiny massif, Kola Peninsula, Russia. Link to MinDat.org Location Data.

Name Origin:

Named for Mstislav Vsevolodovich Keldysh (1911-1978), Russian mathematician and President of the Academy of Sciences, Russia.

Name Pronunciation:

Keldyshite + Pronunciation

Synonym:

ICSD 20186

PDF 24-1097

Keldyshite Image

Images:

Keldyshite

Comments: Gray-white chalk-like keldyshite in and on matrix.
Location: Langdalen, Vestfold, Norway. Scale: Specimen Size 5x7 cm.
© Diederik Visser

Keldyshite Crystallography

Axial Ratios:

a:b:c =0.7995:1:0.6506

Cell Dimensions:

a = 6.66, b = 8.33, c = 5.42, Z = 2; alpha = 92.75°, beta = 94.217°, gamma = 72.33° V = 285.40 Den(Calc)= 3.84

Crystal System:

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

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

By Intensity(I/I_o): 3.99(1), 4.18(0.8), 2.97(0.52),

Crystal Structure:

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Khalikov A D , Khomyakov A P , Makhmudov S A , Doklady Akademii Nauk SSSR , 238 (1978) p.573-575, Crystal structure of keldyshite NaZr[Si2O6OH]

Physical Properties of Keldyshite

Cleavage:

{???} Indistinct, {???} Indistinct

Color:

White.

Density:

3.3

Diaphaneity:

Transparent to Translucent

Fracture:

Brittle - Uneven - Very brittle fracture producing uneven fragments.

Hardness:

3.5-4.5 - Between Copper Penny and Fluorite-Apatite

Luster:

Vitreous - Greasy

Streak:

white

Optical Properties of Keldyshite

Gladstone-Dale:

CI meas= 0.061 (Fair) - where the CI = (1-KPDmeas/KC)
CI calc= 0.193 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1797,KPDmeas= 0.2091,KC= 0.2228
Ncalc = 1.74 - 1.86

Optical Data:

Biaxial (?), a=1.67, g=1.71, bire=0.0400, 2V(Meas)=60.

Calculated Properties of Keldyshite

Electron Density:

Bulk Density (Electron Density)=3.22 gm/cc
note: Specific Gravity of Keldyshite =3.30 gm/cc.

Fermion Index:

Fermion Index = 0.03
Boson Index = 0.97

Photoelectric:

PE_Keldyshite= 37.28 barns/electron
U=PE_Keldyshite x rElectron Density= 119.90 barns/cc.

Radioactivity:

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

Keldyshite Classification

Dana Class:

55.02.02.01 (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 Keldyshite Information

References:

NAME( AntBidBlaNic2) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990)

See Also:

Links to other databases for Keldyshite :
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
15 - WWW-MINCRYST

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

Keldyshite

Na2-xHxZrSi2O7•n(H2O)
Dana No: 55.02.02.01 Strunz No: 09.BC.10
Locality:

Notes: