Jeffreyite Mineral Data

General Jeffreyite Information

Chemical Formula:

(Ca,Na)2(Be,Al)Si2(O,OH)7

Composition:

Molecular Weight = 255.30 gm

Sodium 4.50 % Na 6.07 % Na₂O

Calcium 23.55 % Ca 32.95 % CaO

Beryllium 2.65 % Be 7.35 % BeO

Aluminum 2.64 % Al 4.99 % Al₂O₃

Silicon 22.00 % Si 47.07 % SiO₂

Hydrogen 0.79 % H 7.06 % H₂O

Oxygen 43.87 % O

______ ______

100.00 % 105.48 % = TOTAL OXIDE

Empirical Formula:

Ca_1.5Na_0.5Be_0.75Al_0.25Si₂O₅(OH)₂

Environment:

In a cavity in a highly calcium-metasomatized granite dike.

IMA Status:

Approved IMA 1984

Locality:

Jeffrey mine, Asbestos, Quebec, Canada. Link to MinDat.org Location Data.

Name Origin:

Named for the locality.

Name Pronunciation:

Jeffreyite + Pronunciation

Synonym:

IMA1982-075

Jeffreyite Crystallography

Axial Ratios:

a:b:c =1:1:2.712

Cell Dimensions:

a = 14.9, b = 14.9, c = 40.41, Z = 64; V = 8,971.42 Den(Calc)= 3.02

Crystal System:

Orthorhombic - Disphenoidal H-M Symbol (2 2 2) Space Group: C 222₁

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

By Intensity(I/I_o): 2.774(1), 2.993(0.9), 2.541(0.7),

Physical Properties of Jeffreyite

Cleavage:

{001} Perfect, {110} Perfect

Color:

Colorless.

Density:

2.99

Diaphaneity:

Transparent

Fracture:

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

Hardness:

5 - Apatite

Luster:

Vitreous (Glassy)

Streak:

white

Optical Properties of Jeffreyite

Gladstone-Dale:

CI meas= 0.077 (Fair) - where the CI = (1-KPDmeas/KC)
CI calc= 0.086 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2107,KPDmeas= 0.2128,KC= 0.2306
Ncalc = 1.69 - 1.7

Optical Data:

Biaxial (-), a=1.625, b=1.641, g=1.643, bire=0.0180, 2V(Calc)=38, 2V(Meas)=40.

Calculated Properties of Jeffreyite

Electron Density:

Bulk Density (Electron Density)=2.99 gm/cc
note: Specific Gravity of Jeffreyite =2.99 gm/cc.

Fermion Index:

Fermion Index = 0.03
Boson Index = 0.97

Photoelectric:

PE_Jeffreyite= 3.89 barns/electron
U=PE_Jeffreyite x rElectron Density= 11.64 barns/cc.

Radioactivity:

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

Jeffreyite Classification

Dana Class:

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

(55.04)with cations in [8] and lower coordination

(55.04.02)Fresnoite group

55.04.02.01 Fresnoite Ba2TiSi2O8 P 4bm 4mm

55.04.02.02 Hardystonite Ca2ZnSi2O7 P 42₁m 4 2m

55.04.02.03 Jeffreyite (Ca,Na)2(Be,Al)Si2(O,OH)7 C 222₁ 2 2 2

55.04.02.04 Leucophanite (Na,Ca)2BeSi2(O,OH,F)7 P1 1

55.04.02.05 Meliphanite (Ca,Na)2Be[(Si,Al)2O6(F,OH)] I 4 4

55.04.02.06 Gugiaite Ca2BeSi2O7 P 42₁m 4 2m

Strunz Class:

09.BB.10 09 - SILICATES (Germanates)

09.B - Sorosilicates

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

09.BB.10 Akermanite Ca2MgSi2O7 P 42₁m 4 2m

09.BB.10 Cebollite Ca5Al2(SiO4)3(OH)4 Unk Ortho

09.BB.10 Gugiaite Ca2BeSi2O7 P 42₁m 4 2m

09.BB.10 Gehlenite Ca2Al(AlSi)O7 P 42₁m 4 2m

09.BB.10 Jeffreyite (Ca,Na)2(Be,Al)Si2(O,OH)7 C 222₁ 2 2 2

09.BB.10 Hardystonite Ca2ZnSi2O7 P 42₁m 4 2m

09.BB.10 Melilite (Ca,Na)2(Al,Mg,Fe)(Si,Al)2O7 P 42₁m 4 2m

09.BB.10 Okayamalite! Ca2B2SiO7 P 42₁m 4 2m

Other Jeffreyite 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 Jeffreyite :
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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Print or Cut-and-Paste your Jeffreyite Specimen Label here :

Jeffreyite

(Ca,Na)2(Be,Al)Si2(O,OH)7
Dana No: 55.04.02.03 Strunz No: 09.BB.10
Locality:

Notes:

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