Weberite Mineral Data

Weberite Mineral Data +

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General Weberite Information

Chemical Formula:

Na2MgAlF7

Composition:

Molecular Weight = 230.25 gm

Sodium 19.97 % Na 26.92 % Na₂O

Magnesium 10.56 % Mg 17.50 % MgO

Aluminum 11.72 % Al 22.14 % Al₂O₃

Fluorine 57.76 % F 57.76 % F

- % F -24.32 % -O=F₂

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Na₂MgAlF₇

Environment:

With cryolite and other fluorides.

IMA Status:

Valid Species (Pre-IMA) 1938

Locality:

Ivigtut, Greenland. Link to MinDat.org Location Data.

Name Origin:

Named for Theobald C. F. Weber (1823-1886), one of the founders of the cryolite industry in Denmark.

Synonym:

ICSD 33507

PDF 5-733

Weberite Image

Images:

Weberite Cryolite

Comments: Gray weberite masses in white cryolite.
Location: Ivigtut, Greenland. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Weberite Crystallography

Axial Ratios:

a:b:c =0.7059:1:0.7303

Cell Dimensions:

a = 7.06, b = 10, c = 7.303, Z = 4; V = 515.59 Den(Calc)= 2.97

Crystal System:

Orthorhombic - DipyramidalH-M Symbol (2/m 2/m 2/m) Space Group: I mma

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

By Intensity(I/I_o): 1.779(1), 2.89(0.9), 2.95(0.9),

Crystal Structure:

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Giuseppetti G , Tadini C , Tschermaks Mineralogische und Petrographische Mitteilungen , 25 (1978) p.57-62, Re-examination of the crystal structure of weberite, Locality: Ivigtut, Greenland

Physical Properties of Weberite

Cleavage:

[101] Poor, [010] Indistinct

Color:

Greenish, Gray, Grayish white, White.

Density:

2.96

Diaphaniety:

Translucent

Fracture:

Uneven - Flat surfaces (not cleavage) fractured in an uneven pattern.

Habit:

Anhedral Grains - Granular minerals without the expression of crystal shapes

Habit:

Massive - Uniformly indistinguishable crystals forming large masses.

Hardness:

3.5 - Copper Penny

Luster:

Vitreous (Glassy)

Streak:

white

Optical Properties of Weberite

Gladstone-Dale:

CI meas= 0.261 (Poor) - where the CI = (1-KPDmeas/KC)
CI calc= 0.264 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1172,KPDmeas= 0.1176,KC= 0.1591

Optical Data:

Biaxial (+), a=1.346, b=1.348, g=1.35, bire=0.0040, 2V(Calc)=88, 2V(Meas)=83.

Calculated Properties of Weberite

Electron Density:

r_electron=2.83 gm/cc
note: r_Weberite=2.96 gm/cc.

Fermion Index

Fermion Index = 0.01055
Boson Index = 0.98945

Photoelectric:

PE_Weberite= 1.18 barns/electron
U=PE_Weberite x r_electron= 3.34 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Weberite is Not Radioactive

Weberite Classification

Dana Class:

11.6.13.1 (11)Halide Complexes; Alumino-fluorides

(11.6)with miscellaneous formulae

(11.6.13)Dana Group

11.6.13.1 Weberite Na2MgAlF7 I mma 2/m 2/m 2/m

Strunz Class:

III/C.03-30 III - Halogenides

III/C - Double halogenides with water, Fluorides

III/C.03 - Prosopite - Boldyrevite series

III/C.03-10 Prosopite CaAL2(F,OH)8 A2/a 2/m

III/C.03-20 Chiolite Na5Al3F14 P 4/mnc 4/m 2/m 2/m

III/C.03-30 Weberite Na2MgAlF7 I mma 2/m 2/m 2/m

III/C.03-40 Usovite Ba2CaMgAl2F14 C 2/c or Cc Mono

III/C.03-45 Karasugite SrCaAl(F,OH)7 P 2₁/c 2/m

III/C.03-50 Carlhintzeite Ca2AlF7·(H2O) C1,C1 Tri

III/C.03-55 Rosenbergite AlF3·3(H2O) P 4/n 4/m

III/C.03-60 Ralstonite NaxMgxAl2-x(F,OH)6·(H2O) F d3m 4/m 3 2/m

III/C.03-70 Neighborite NaMgF3 Pcmn 2/m 2/m 2/m

III/C.03-80 Boldyrevite* NaCaMgAl3F14·4(H2O) None

Other Weberite Information

References:

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

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

Weberite

Na2MgAlF7
Dana No: 11.6.13.1 Strunz No: III/C.03-30
Locality:

Notes: