Cobaltarthurite Mineral Data

Cobaltarthurite Mineral Data

General Cobaltarthurite Information

Chemical Formula:

CoFe+++2(AsO4)2(OH)2·4(H2O)

Composition:

Molecular Weight = 533.48 gm

Magnesium 0.46 % Mg 0.76 % MgO

Manganese 1.03 % Mn 1.33 % MnO

Iron 21.98 % Fe 31.43 % Fe₂O₃

Cobalt 5.52 % Co 7.02 % CoO

Arsenic 28.09 % As 43.08 % As₂O₅

Hydrogen 1.83 % H 16.38 % H₂O

Oxygen 41.09 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Co_0.5Mg_0.1Fe³⁺_0.1Mn²⁺_0.1Fe³⁺₂(AsO₄)₂(OH)_1.7·4(H₂O)

Environment:

Secondary mineral in a near surface, sulfide-depleted lens (Dolores showing). (Co-dominant analogue of arthurite; structure)

IMA Status:

Approved IMA 2002 (Dana # Added)

Locality:

Patrana (a village about 10 km east of Mazzarron), Province of Murcia, SE Spain. Link to MinDat.org Location Data.

Name Origin:

Named as the Co-dominant member of the arthurite group.

Synonym:

IMA2001-052

Cobaltarthurite Image

Images:

Click Here for Larger Cobaltarthurite Image

Cobaltarthurite Arseniosiderite

Comments: Olive-greenish crystalline druse of cobaltarthurite with spherical arseniosiderite.
Location: Pastrana, Mazarr?n, Murcia, Spain. Scale: Picture size 1.3 mm.
© Thomas Witzke / Abraxas-Verlag

Cobaltarthurite Crystallography

Axial Ratios:

a:b:c =1.0565:1:0.5704

Cell Dimensions:

a = 10.27, b = 9.72, c = 5.545, Z = 2; beta = 94.46° V = 551.85 Den(Calc)= 3.21

Crystal System:

Monoclinic - PrismaticH-M Symbol (2/m) Space Group: P 2₁/c

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

By Intensity(I/I_o): 7.04(1)(110), 10.2(0.95)(100), 4.81(0.65)(001),3.05(0.6), 4.24(0.6)(111), 2.87(0.55)(311), 2.89(0.25)(221), 4.51(0.2),

Crystal Structure:

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Raudsepp M , Pani E , The Canadian Mineralogist , 40 (2002) p.733-737, The crystal structure of cobaltarthurite, CoFe2(AsO4)2(OH)2.4H2O:, A Rietveld refinement

View Additional jPOWD Structure files for Cobaltarthurite
[1]

Physical Properties of Cobaltarthurite

Cleavage:

None

Color:

Straw yellow, Dark brown.

Density:

3.22

Diaphaniety:

Translucent

Fracture:

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

Habit:

Globular - Spherical, or nearly so, rounded forms (e.g. wavellite).

Habit:

Massive - Uniformly indistinguishable crystals forming large masses.

Habit:

Oolitic - < 3mm rounded spherical grains.

Hardness:

3.5-4 - Copper Penny-Fluorite

Luster:

Vitreous - Silky

Streak:

light brownish white

Optical Properties of Cobaltarthurite

Gladstone-Dale:

CI meas= 0.013 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= 0.01 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2388,KPDmeas= 0.2381,KC= 0.2412

Optical Data:

Biaxial (+), a=1.741, b=1.762, g=1.797, bire=0.0560

Calculated Properties of Cobaltarthurite

Electron Density:

r_electron=3.09 gm/cc
note: r_{Cobaltarthurite}=3.21 gm/cc.

Fermion Index

Fermion Index = 0.00531
Boson Index = 0.99469

Photoelectric:

PE_{Cobaltarthurite}= 27.71 barns/electron
U=PE_{Cobaltarthurite} x r_electron= 85.74 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Cobaltarthurite is Not Radioactive

Cobaltarthurite Classification

Dana Class:

42.11.18.6 (42)Hydrated Phosphates, etc., Containing Hydroxyl or Halogen

(42.11)where (AB)4 (XO4)3 Zq · x(H2O)

(42.11.18)Dana Group

42.11.18.1 Whitmoreite FeFe2(PO4)2(OH)2·4(H2O) P 2₁/c 2/m

42.11.18.2 Arthurite CuFe2(AsO4,PO4,SO4)2(O,OH)2·4(H2O) P 2₁/c 2/m

42.11.18.3 Ojuelaite ZnFe2(AsO4)2(OH)2·4(H2O) P 2₁/c 2/m

42.11.18.4 Earlshannonite (Mn,Fe)Fe2(PO4)2(OH)2·4(H2O) P 2₁/c 2/m

42.11.18.5 Gladiusite! Fe2(Fe,Mg)4(PO4)(OH)13·H2O P 2₁/n 2/m

42.11.18.6 Cobaltarthurite ! CoFe2(AsO4)2(OH)2·4(H2O) P 2₁/c 2/m

Strunz Class:

VII/D.08-45 VII - Phosphates, Arsenates and Vanadates

VII/D - Water-bearing phosphates with unfamiliar anions, cations of medium size: Cu, Zn, Mn, Al, Fe

VII/D.08 - Arthurite group

VII/D.08-10 Kleemanite ZnAl2(PO4)2(OH)2·3(H2O) P 2, P 2₁, P 2/m or P 2₁/m Mono

VII/D.08-20 Whitmoreite FeFe2(PO4)2(OH)2·4(H2O) P 2₁/c 2/m

VII/D.08-30 Earlshannonite (Mn,Fe)Fe2(PO4)2(OH)2·4(H2O) P 2₁/c 2/m

VII/D.08-40 Arthurite CuFe2(AsO4,PO4,SO4)2(O,OH)2·4(H2O) P 2₁/c 2/m

VII/D.08-45 Cobaltarthurite CoFe2(AsO4)2(OH)2·4(H2O) P 2₁/c 2/m

VII/D.08-50 Ojuelaite ZnFe2(AsO4)2(OH)2·4(H2O) P 2₁/c 2/m

VII/D.08-60 Mapimite Zn2Fe3(AsO4)3(OH)4·10(H2O) Cm m

Other Cobaltarthurite Information

References:

NAME( AmMin, Vol 88, p 475) PHYS. PROP.(AmMin, Vol 88, p 475) OPTIC PROP.(AmMin, Vol 88, p 475)

See Also:

Links to other databases for Cobaltarthurite :
1 -Am. Min. Crystal Structure Database 2 -Athena 3 -Google Images 4 -Google Scholar 5 -MinDAT 6 -MinMax(Deutsch) 7 -MinMax(English) 8 -Mineralienatlas (Deutsch) 9 -QUT Mineral Atlas

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Cobaltarthurite

CoFe+++2(AsO4)2(OH)2·4(H2O)
Dana No: 42.11.18.6 Strunz No: VII/D.08-45
Locality:

Notes: