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 % Fe2 O3
Cobalt 5.52 % Co 7.02 % CoO
Arsenic 28.09 % As 43.08 % As2 O5
Hydrogen 1.83 % H 16.38 % H2 O
Oxygen 41.09 % O
______ ______
100.00 % 100.00 % = TOTAL OXIDE
Empirical Formula:
Co0.5 Mg0.1 Fe3+ 0.1 Mn2+ 0.1 Fe3+ 2 (AsO4 )2 (OH)1.7 �4(H2 O)
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:
Cobaltarthurite Crystallography
Axial Ratios:
a:b:c =1.0577:1:0.5741
Cell Dimensions:
a = 10.2635, b = 9.7028, c = 5.5711, Z = 2; beta = 94.207° V = 553.30 Den(Calc)= 3.20
Crystal System:
Monoclinic - Prismatic H-M Symbol (2/m) Space Group: P 21 /c
X Ray Diffraction:
By Intensity(I/Io ): 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),
Physical Properties of Cobaltarthurite
Cleavage:
None
Color:
Straw yellow, Dark brown.
Density:
3.22
Diaphaneity:
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 = 0.007 (Superior) - where the CI = (1-KPDcalc /KC )
KPDcalc = 0.2396,KPDmeas = 0.2381,KC = 0.2412 Ncalc = 1.77 - 1.78
Optical Data:
Biaxial (+), a=1.741, b=1.762, g=1.797, bire=0.0560
Calculated Properties of Cobaltarthurite
Electron Density:
Bulk Density (Electron Density)=3.08 gm/cc note: Specific Gravity of Cobaltarthurite =3.20 gm/cc.
Fermion Index:
Fermion Index = 0.0053160916 Boson Index = 0.9946839084
Photoelectric:
PECobaltarthurite = 27.71 barns/electronU=PECobaltarthurite x r Electron Density= 85.48 barns/cc.
Radioactivity:
GRapi = 0 (Gamma Ray American Petroleum Institute Units) Cobaltarthurite is Not Radioactive
Cobaltarthurite Classification
Dana Class:
42.11.18.06 (42) Hydrated Phosphates, etc., Containing Hydroxyl or Halogen
(42.11) where (AB)4 (XO4)3 Zq � x(H2O)
(42.11.18) Whitmoreite Group
42.11.18.01 Whitmoreite FeFe2(PO4)2(OH)2•4(H2O) P 21 /c 2/m
42.11.18.02 Arthurite CuFe2(AsO4,PO4,SO4)2(O,OH)2•4(H2O) P 21 /c 2/m
42.11.18.03 Ojuelaite ZnFe2(AsO4)2(OH)2•4(H2O) P 21 /c 2/m
42.11.18.04 Earlshannonite (Mn,Fe)Fe2(PO4)2(OH)2•4(H2O) P 21 /c 2/m
42.11.18.05 Gladiusite ! Fe2(Fe,Mg)4(PO4)(OH)13•H2O P 21 /n 2/m
42.11.18.06 Cobaltarthurite ! CoFe2(AsO4)2(OH)2•4(H2O) P 21 /c 2/m
42.11.18.07 Kunatite CuFe2(PO4)2(OH)2•4H2O P 21 /c 2/m
42.11.18.08 Bendadaite ! FeFe2(AsO4)2(OH)2•4H2O P 21 /c 2/m
Strunz Class:
08.DC.15 08 - PHOSPHATES, ARSENATES, VANADATES
08.D - Phosphates, etc
08.DC -With only medium-sized cations, (OH, etc.):RO4 = 1:1 and < 2:1
08.DC.15 Earlshannonite (Mn,Fe)Fe2(PO4)2(OH)2•4(H2O) P 21 /c 2/m
08.DC.15 Arthurite CuFe2(AsO4,PO4,SO4)2(O,OH)2•4(H2O) P 21 /c 2/m
08.DC.15 Ojuelaite ZnFe2(AsO4)2(OH)2•4(H2O) P 21 /c 2/m
08.DC.15 Whitmoreite FeFe2(PO4)2(OH)2•4(H2O) P 21 /c 2/m
08.DC.15 Cobaltarthurite ! CoFe2(AsO4)2(OH)2•4(H2O) P 21 /c 2/m
08.DC.15 Kunatite CuFe2(PO4)2(OH)2•4H2O P 21 /c 2/m
08.DC.15 Bendadaite ! FeFe2(AsO4)2(OH)2•4H2O P 21 /c 2/m
Other Cobaltarthurite Information
References:
NAME( AmMin, Vol 88, p 475) PHYS. PROP.(AmMin, v88, p475; v91, p715) OPTIC PROP.(AmMin, Vol 88, p 475)
See Also:
Links to other databases for Cobaltarthurite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - GeoScienceWorld
4 - Google Images
5 - Google Scholar
6 - MinDAT
7 - Mineralienatlas (Deutsch)
8 - Online Mineral Museum
9 - QUT Mineral Atlas
10 - Ruff.Info
Search for Cobaltarthurite using:
[AOL ]
[Bing ]
[Dog Pile ]
[GeoScienceWorld ]
[HotBot ]
[Ixquick ]
[Lycos ]
[MAMMA ]
[Scirus ]
[Teoma ]
[WebCrawler ]
[Wikipedia ]
[YAHOO ]
Visit our Advertisers for Cobaltarthurite :
Ask about Cobaltarthurite here :
Ask-A-Mineralogist from the Mineralogical Society of America
Mindat.org's Discussion Groups
Original Rockhounds Discussion Group
Rockhounds Discussion Group on Yahoo Groups
Mineral Discussion Forum from Fabre Minerals - also available in
Espa�ol
Print or Cut-and-Paste your Cobaltarthurite Specimen Label here :
Cobaltarthurite
CoFe+++2(AsO4)2(OH)2•4(H2O)
Dana No: 42.11.18.06 Strunz No: 08.DC.15
Locality:
Notes:
Dakota Matrix
Excalibur Minerals
Exceptional Minerals
Hudson Insitute
John Betts Fine Minerals
Mc Dougall Minerals
Mineral News
Rock and Mineral Shows
Weinrich Minerals, Inc.