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Cassidyite

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Formula:
Ca
 
2
(Ni
2+
 
,Mg)(PO
 
4
)
 
2
 · 2H
 
2
O
System:TriclinicHardness:3½
Member of:Fairfieldite Group
Name:
For US geologist William A. Cassidy.


Fairfieldite Group.

Classification of Cassidyite

IMA status:Approved 1966
Strunz 8th edition ID:7/C.17-40
Nickel-Strunz 10th (pending) edition ID:8.CG.05

8 : PHOSPHATES, ARSENATES, VANADATES
C : Phosphates without additional anions, with H2O
G : With large and medium-sized cations, RO4:H2O = 1:1
Dana 8th edition ID:40.2.2.4

40 : HYDRATED NORMAL PHOSPHATES,ARSENATES AND VANADATES
2 : AB2(XO4)2·xH2O
Hey's CIM Ref.:19.15.2

19 : Phosphates
15 : Phosphates of Ni
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Type Occurrence of Cassidyite

Type Locality:Wolf Creek meteorite crater, Western Australia, Australia

Physical Properties of Cassidyite

Hardness (Mohs):3½

Crystallography of Cassidyite

Crystal System:Triclinic
Cell Parameters:a = 5.71Å, b = 6.73Å, c = 5.41Å
α = 96.83°, β = 107.37°, γ = 104.58°
Ratio:a:b:c = 0.848 : 1 : 0.804
Unit Cell Volume:V 187.74 ų (Calculated from Unit Cell)

Optical Data of Cassidyite

Type:Biaxial
RI values: nα = 1.640 - 1.650 nγ = 1.670
Maximum Birefringence:δ = 0.030

Chart shows birefringence interference colour range (at 30µm thickness) and does not take into account mineral colouration.
Surface Relief:Moderate
Dispersion:relatively strong

Chemical Properties of Cassidyite

Formula:
Ca
 
2
(Ni
2+
 
,Mg)(PO
 
4
)
 
2
 · 2H
 
2
O
Essential elements:Ca, H, Ni, O, P
All elements listed in formula:Ca, H, Mg, Ni, O, P

Relationship of Cassidyite to other Species

Member of:Fairfieldite Group
Other Members of Group:

- +
Collinsite
Ca
 
2
(Mg,Fe
2+
 
)(PO
 
4
)
 
2
 · 2H
 
2
O
Fairfieldite
Ca
 
2
(Mn
2+
 
,Fe
2+
 
)(PO
 
4
)
 
2
 · 2H
 
2
O
Gaitite
Ca
 
2
Zn(AsO
 
4
)
 
2
 · 2H
 
2
O
Messelite
Ca
 
2
(Fe
2+
 
,Mn
2+
 
)(PO
 
4
)
 
2
 · 2H
 
2
O
Nickeltalmessite
Ca
 
2
Ni(AsO
 
4
)
 
2
 · 2H
 
2
O
Parabrandtite
Ca
 
2
Mn
2+
 
(AsO
 
4
)
 
2
 · 2H
 
2
O
Talmessite
Ca
 
2
Mg(AsO
 
4
)
 
2
 · 2H
 
2
O
β-Roselite
Ca
 
2
(Co
2+
 
,Mg)(AsO
 
4
)
 
2
 · 2H
 
2
O
Related Minerals - Nickel-Strunz Grouping):

- +
8.CG.05Collinsite
Ca
 
2
(Mg,Fe
2+
 
)(PO
 
4
)
 
2
 · 2H
 
2
O
8.CG.05Fairfieldite
Ca
 
2
(Mn
2+
 
,Fe
2+
 
)(PO
 
4
)
 
2
 · 2H
 
2
O
8.CG.05Gaitite
Ca
 
2
Zn(AsO
 
4
)
 
2
 · 2H
 
2
O
8.CG.05Messelite
Ca
 
2
(Fe
2+
 
,Mn
2+
 
)(PO
 
4
)
 
2
 · 2H
 
2
O
8.CG.05Parabrandtite
Ca
 
2
Mn
2+
 
(AsO
 
4
)
 
2
 · 2H
 
2
O
8.CG.05Talmessite
Ca
 
2
Mg(AsO
 
4
)
 
2
 · 2H
 
2
O
8.CG.05β-Uranophane
Ca(UO
 
2
)
 
2
(HSiO
 
4
)
 
2
 · 5H
 
2
O
8.CG.05Hillite
Ca
 
2
(Zn,Mg)(PO
 
4
)
 
2
 · 2 H
 
2
O
8.CG.10Brandtite
Ca
 
2
(Mn
2+
 
,Mg)(AsO
 
4
)
 
2
 · 2H
 
2
O
8.CG.10Roselite
Ca
 
2
(Co
2+
 
,Mg)(AsO
 
4
)
 
2
 · 2H
 
2
O
8.CG.10Wendwilsonite
Ca
 
2
(Mg,Co
2+
 
)(AsO
 
4
)
 
2
 · 2H
 
2
O
8.CG.10Zincroselite
Ca
 
2
Zn(AsO
 
4
)
 
2
 · 2H
 
2
O
8.CG.10Rruffite
Ca
 
2
Cu(AsO
 
4
)
 
2
 · 2H
 
2
O
8.CG.15Ferrilotharmeyerite
Ca(Fe
3+
 
,Zn)
 
2
(AsO
 
4
)
 
2
 · 2(OH,H
 
2
O)
8.CG.15Lotharmeyerite
Ca(Zn,Mn
3+
 
)
 
2
(AsO
 
4
)
 
2
 · 2(H
 
2
O,OH)
8.CG.15Mawbyite
Pb(Fe
3+
 
,Zn)
 
2
(AsO
 
4
)
 
2
 · 2(OH,H
 
2
O)
8.CG.15Mounanaite
PbFe
3+
2
(VO
 
4
)
 
2
 · 2(OH,F)
8.CG.15Thometzekite
Pb(Cu,Zn)
 
2
(AsO
 
4
,SO
 
4
)
 
2
 · 2(H
 
2
O,OH)
8.CG.15Tsumcorite
Pb(Zn,Fe
3+
 
)
 
2
(AsO
 
4
)
 
2
 · 2(H
 
2
O,OH)
8.CG.15Cobaltlotharmeyerite
Ca(Co,Fe
3+
 
,Ni)
 
2
(AsO
 
4
)
 
2
 · 2(H
 
2
O,OH)
8.CG.15Cabalzarite
Ca(Mg,Al,Fe
3+
 
)
 
2
(AsO
 
4
)
 
2
 · 2(OH,H
 
2
O)
8.CG.15Krettnichite
(Pb,Sr)(Mn
3+
 
,Co)
 
2
(VO
 
4
)
 
2
 · 2(OH,H
 
2
O)
8.CG.15Cobalttsumcorite
Pb(Co,Fe
3+
 
,Ni)
 
2
(AsO
 
4
)
 
2
 · 2(H
 
2
O,OH)
8.CG.15Nickellotharmeyerite
Ca(Ni,Fe
3+
 
,Co)
 
2
(AsO
 
4
)
 
2
 · 2(H
 
2
O,OH)
8.CG.15Manganlotharmeyerite
Ca(Mn
3+
 
,Zn)
 
2
(AsO
 
4
)
 
2
 · 2(OH,H
 
2
O)
8.CG.15Schneebergite
(Bi
3+
 
,Ca)(Co,Ni,Fe
3+
 
)
 
2
(AsO
 
4
)
 
2
 · 2(OH,H
 
2
O)
8.CG.15Nickelschneebergite
(Bi
3+
 
,Ca)(Ni,Co,Fe
3+
 
)
 
2
(AsO
 
4
)
 
2
 · 2(OH,H
 
2
O)
8.CG.20Gartrellite
Pb(Cu,Fe
3+
 
,Zn)
 
2
(AsO
 
4
,SO
 
4
)
 
2
 · 2(H
 
2
O,OH)
8.CG.20Helmutwinklerite
Pb(Zn,Cu)
 
2
(AsO
 
4
)
 
2
 · 2H
 
2
O
8.CG.20Zincgartrellite
Pb(Zn,Fe
3+
 
,Cu)
 
2
(AsO
 
4
)
 
2
 · 2(H
 
2
O,OH)
8.CG.20Rappoldite
Pb(Co,Ni,Zn)
 
2
(AsO
 
4
)
 
2
 · 2H
 
2
O
8.CG.20Phosphogartrellite
Pb(Cu,Fe
3+
 
)
 
2
(PO
 
4
,AsO
 
4
)
 
2
 · 2(H
 
2
O,OH)
8.CG.20Lukrahnite
Ca(Cu,Zn)(Fe
3+
 
,Zn)(AsO
 
4
)
 
2
 · 2(H
 
2
O,OH)
8.CG.25Pottsite
HPbBi(VO
 
4
)
 
2
 · 2H
 
2
O
8.CG.35Nickeltalmessite
Ca
 
2
Ni(AsO
 
4
)
 
2
 · 2H
 
2
O
Related Minerals - Hey's Index Grouping:

- +
19.15.1Arupite
Ni
 
3
(PO
 
4
)
 
2
 · 8H
 
2
O

Other Names for Cassidyite

Synonyms:
IMA1966-024
Other Languages:
German:Cassidyit
Russian:Кассидиит
Spanish:Cassidyita

Other Information

Health Warning:No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.

References for Cassidyite

Reference List:

- +
American Mineralogist: 52: 1190-1197(1967)

Internet Links for Cassidyite

Search Engines:
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    • External Links:
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  • Raman and XRD data at RRUFF project
  • American Mineralogist Crystal Structure Database
  • Cassidyite details from Handbook of Mineralogy (PDF)
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    • Localities for Cassidyite

    The map shows a selection of localities that have latitude and longitude coordinates recorded. Click on the symbol to view information about a locality. The symbol next to localities in the list can be used to jump to that position on the map.
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    (TL) indicates type locality. ? indicates mineral may be doubtful at this locality. All other localities listed without reference should be considered as uncertain and unproven until references can be found.
    Australia
     
    • Western Australia
    		AM 52 (1967), 1190; HB4 (2000)
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    Copyright © Jolyon Ralph and Ida Chau 1993-2011. Site Map. Locality, mineral & photograph data are the copyright of the individuals who submitted them.Further information contact the Site hosted & developed by Jolyon Ralph. Mindat.org is an online information resource dedicated to providing free mineralogical information to all. Mindat relies on the contributions of hundreds of members and supporters. Mindat does not offer minerals for sale. If you would like to add information to improve the quality of our database, then click here to register. Current server date and time: 21st Jun 2011 12:59:35
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