Cassidyite Mineral Data

General Cassidyite Information

Chemical Formula:

Ca2(Ni,Mg)(PO4)2•2(H2O)

Composition:

Molecular Weight = 356.22 gm

Calcium 22.50 % Ca 31.48 % CaO

Magnesium 1.71 % Mg 2.83 % MgO

Nickel 12.36 % Ni 15.73 % NiO

Phosphorus 17.39 % P 39.85 % P₂O₅

Hydrogen 1.13 % H 10.11 % H₂O

Oxygen 44.91 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Ca₂Ni_0.75Mg_0.25(PO₄)₂•2(H₂O)

Environment:

Alteration product of a highly weathered iron-nickel meteorite, formed by alteration of schreibersite.

IMA Status:

Approved IMA 1967

Locality:

Wolf Creek meteorite. Link to MinDat.org Location Data.

Name Origin:

Named for William A. Cassidy, who mapped the Wolf Creek, Australia, crater in 1953.

Cassidyite Crystallography

Axial Ratios:

a:b:c =0.8484:1:0.8038

Cell Dimensions:

a = 5.71, b = 6.73, c = 5.41, Z = 1; alpha = 96.83°, beta = 107.4°, gamma = 104.6° V = 190.62 Den(Calc)= 3.10

Crystal System:

Triclinic - Pinacoidal H-M Symbol ( 1) Space Group: P1

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

By Intensity(I/I_o): 2.7(1), 3.03(0.95), 2.67(0.79),

Physical Properties of Cassidyite

Color:

Green, Light green.

Density:

3.1

Diaphaneity:

Transparent

Hardness:

3.5 - Copper Penny

Luster:

Vitreous (Glassy)

Optical Properties of Cassidyite

Gladstone-Dale:

CI meas= -0.026 (Excellent) - where the CI = (1-KPDmeas/KC)
CI calc= -0.01 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2087,KPDmeas= 0.2121,KC= 0.2068
Ncalc = 1.64 - 1.65

Optical Data:

Biaxial (?), a=1.64-1.65, g=1.67, bire=0.0200-0.0300

Calculated Properties of Cassidyite

Electron Density:

Bulk Density (Electron Density)=3.15 gm/cc
note: Specific Gravity of Cassidyite =3.15 gm/cc.

Fermion Index:

Fermion Index = 0.00362311
Boson Index = 0.99637689

Photoelectric:

PE_Cassidyite= 8.45 barns/electron
U=PE_Cassidyite x rElectron Density= 26.59 barns/cc.

Radioactivity:

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

Cassidyite Classification

Dana Class:

40.02.02.04 (40)Hydrated Phosphates, etc

(40.02)where A++ (B++)2 (XO4) ï¿½ x(H2O)

(40.02.02)Fairfieldite Subgroup (Triclinic: P-1ï¿½)

40.02.02.01 Fairfieldite Ca2(Mn,Fe)(PO4)2•2(H2O) P1 1

40.02.02.02 Messelite Ca2(Fe,Mn)(PO4)2•2(H2O) P1 1

40.02.02.03 Collinsite Ca2(Mg,Fe)(PO4)2•2(H2O) P1 1

40.02.02.04 Cassidyite Ca2(Ni,Mg)(PO4)2•2(H2O) P1 1

40.02.02.05 Talmessite Ca2Mg(AsO4)2•2(H2O) P1 1

40.02.02.06 Gaitite Ca2Zn(AsO4)2•2(H2O) P1 1

40.02.02.07 Roselite-beta Ca2(Co,Mg)(AsO4)2•2(H2O) P 1 or P1 Tri

40.02.02.08 Parabrandtite Ca2Mn(AsO4)•2(H2O) P1,P 1 Tri

40.02.02.09 Hillite! Ca2(Zn,Mg)[PO4]2•2(H2O) P1 1

40.02.02.10 Nickeltalmessite! Ca2Ni(AsO4)2•2H2O P 1

Strunz Class:

08.CG.05 08 - PHOSPHATES, ARSENATES, VANADATES

08.C - Phosphates without Additional Anions, with H2O

08.CG -With large and medium-sized cations, RO4:H2O = 1:1

08.CG.05 Collinsite Ca2(Mg,Fe)(PO4)2•2(H2O) P1 1

08.CG.05 Gaitite Ca2Zn(AsO4)2•2(H2O) P1 1

08.CG.05 Cassidyite Ca2(Ni,Mg)(PO4)2•2(H2O) P1 1

08.CG.05 Fairfieldite Ca2(Mn,Fe)(PO4)2•2(H2O) P1 1

08.CG.05 Messelite Ca2(Fe,Mn)(PO4)2•2(H2O) P1 1

08.CG.05 Parabrandtite Ca2Mn(AsO4)•2(H2O) P1,P 1 Tri

08.CG.05 Uranophane-beta Ca[(UO2)SiO3(OH)]2•(H2O) P 2₁/a 2/m

08.CG.05 Talmessite Ca2Mg(AsO4)2•2(H2O) P1 1

08.CG.05 Hillite! Ca2(Zn,Mg)[PO4]2•2(H2O) P1 1

Other Cassidyite Information

References:

NAME( AntBidBlaNic4) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990)

See Also:

Links to other databases for Cassidyite :
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 Cassidyite Specimen Label here :

Cassidyite

Ca2(Ni,Mg)(PO4)2•2(H2O)
Dana No: 40.02.02.04 Strunz No: 08.CG.05
Locality:

Notes:

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