Weddellite Mineral Data

Weddellite Mineral Data +

General Weddellite Information

Chemical Formula:

Ca(C2O4)·2(H2O)

Composition:

Molecular Weight = 164.13 gm

Calcium 24.42 % Ca 34.17 % CaO

Hydrogen 2.46 % H 21.95 % H₂O

Carbon 14.64 % C 43.88 % C₂O₃

Oxygen 58.49 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Ca(C₂O₄)·2(H₂O)

IMA Status:

Valid Species (Pre-IMA) 1942

Locality:

Link to MinDat.org Location Data.

Name Origin:

Named for the Weddel sea, Antactica.

Synonym:

Calcium Oxalate

ICSD 30783

PDF 17-541

Weddellite Image

Images:

Weddellite

Comments: Tan prismatic weddellite crystal sprays in vug.
Location: Near Biggs, Wasco County, Oregon, USA. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Weddellite Crystallography

Axial Ratios:

a:c = 1:0.59635

Cell Dimensions:

a = 12.33, c = 7.353, Z = 8; V = 1,117.87 Den(Calc)= 1.95

Crystal System:

Tetragonal - DipyramidalH-M Symbol (4/m) Space Group: I 4/m

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

By Intensity(I/I_o): 6.18(1), 2.775(0.65), 4.42(0.3),

Crystal Structure:

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Tazzoli V , Domeneghetti M C , American Mineralogist , 65 (1980) p.327-334, The crystal structures of whewellite and weddellite: re-examination and, comparison

Physical Properties of Weddellite

Cleavage:

[010] Good

Color:

Colorless, Tan, White, Yellowish brown, Brown.

Density:

2.02

Diaphaniety:

Transparent

Hardness:

4 - Fluorite

Luster:

Vitreous (Glassy)

Streak:

white

Optical Properties of Weddellite

Gladstone-Dale:

CI meas= -0.804 (Poor) - where the CI = (1-KPDmeas/KC)
CI calc= -0.869 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2736,KPDmeas= 0.2641,KC= 0.1464

Optical Data:

Uniaxial (+), w=1.523, e=1.544, bire=0.0210.

Calculated Properties of Weddellite

Electron Density:

r_electron=2.07 gm/cc
note: r_Weddellite=2.02 gm/cc.

Fermion Index

Fermion Index = 0.00222
Boson Index = 0.99778

Photoelectric:

PE_Weddellite= 3.15 barns/electron
U=PE_Weddellite x r_electron= 6.51 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Weddellite is Not Radioactive

Weddellite Classification

Dana Class:

50.1.2.1 (50)Salts of Organic Acids

(50.1)(Oxalates)

(50.1.2)Dana Group

50.1.2.1 Weddellite Ca(C2O4)·2(H2O) I 4/m 4/m

50.1.2.2 Caoxite! Ca(C2O4)·3(H2O) P1 1

Strunz Class:

IX/A.01-20 IX - Organic compunds

IX/A - Oxalates. Salts from organic acids. [C2O4]2- arranged after increasing cation size

IX/A.01 - Whewellite - Wheatleyite series

IX/A.01-05 Natroxalate! Na2C2O4 P 2₁/a 2/m

IX/A.01-10 Whewellite Ca(C2O4)·(H2O) P 2₁/n 2/m

IX/A.01-20 Weddellite Ca(C2O4)·2(H2O) I 4/m 4/m

IX/A.01-25 Caoxite! Ca(C2O4)·3(H2O) P1 1

IX/A.01-28 Novgorodovaite! Ca2(C2O4)Cl2·2(H2O) I2/m 2/m

IX/A.01-30 Oxammite (NH4)2(C2O4)·(H2O) P 2₁2₁2 2 2 2

IX/A.01-40 Glushinskite Mg(C2O4)·2(H2O) C 2/c 2/m

IX/A.01-50 Humboldtine Fe(C2O4)·2(H2O) I2/a 2/m

IX/A.01-55 Lindbergite! Mn(C2O4)·2(H2O) C 2/c 2/m

IX/A.01-60 Minguzzite K3Fe(C2O4)3·3(H2O) P 2₁/c 2/m

IX/A.01-70 Zhemchuzhnikovite NaMg(Al,Fe)(C2O4)3·8(H2O) Unk Trig

IX/A.01-80 Stepanovite NaMgFe(C2O4)3·8-9(H2O) Unk Trig

IX/A.01-90 Moolooite Cu(C2O4)·n(H2O)(n<1) Unk Ortho

IX/A.01-100 Wheatleyite Na2Cu(C2O4)2·2(H2O) P1 1

IX/A.01-110 Coskrenite-(Ce)! (Ce,Nd,La)2(SO4)2(C2O4)·8(H2O) C 2/c 2/m

IX/A.01-120 Levinsonite-(Y)! (Y,Nd,La)Al(SO4)2(C2O4)·12(H2O) P 2/n 2/m

IX/A.01-130 Zugshunstite-(Ce)! (Ce,Nd,La)Al(SO4)2(C2O4)·8(H2O) C 2/c 2/m

Other Weddellite Information

References:

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

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Weddellite

Ca(C2O4)·2(H2O)
Dana No: 50.1.2.1 Strunz No: IX/A.01-20
Locality:

Notes: