Cobaltneustädtelite
A valid IMA mineral species
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About Cobaltneustädtelite
Formula:
Bi2Fe3+(Co,Fe3+)(AsO4)2(O,OH)4
Colour:
Brown, red-brown
Lustre:
Adamantine
Hardness:
4½
Specific Gravity:
5.81 (Calculated)
Crystal System:
Triclinic
Name:
In allusion to its composition, containing dominant cobalt, and its relationship to neustädtelite.
Name Encoding
ASCII-7:
Cobaltneustadtelite
Unique Identifiers
Mindat ID:
11015
Long-form identifier:
mindat:1:1:11015:4
IMA Classification of Cobaltneustädtelite
Approved
IMA Formula:
Bi3+2Fe3+(Co2+,Fe3+)(As5+O4)2(O,OH)4
Approval year:
2000
First published:
2002
Classification of Cobaltneustädtelite
8.BK.10
8 : PHOSPHATES, ARSENATES, VANADATES
B : Phosphates, etc., with additional anions, without H2O
K : With medium-sized and large cations, (OH, etc.):RO4 = 2:1, 2.5:1
8 : PHOSPHATES, ARSENATES, VANADATES
B : Phosphates, etc., with additional anions, without H2O
K : With medium-sized and large cations, (OH, etc.):RO4 = 2:1, 2.5:1
Mineral Symbols
As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
| Symbol | Source | Reference for Standard |
|---|---|---|
| Cneu | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
Physical Properties of Cobaltneustädtelite
Adamantine
Transparency:
Transparent, Translucent
Colour:
Brown, red-brown
Streak:
Light brown
Hardness:
4½ on Mohs scale
Tenacity:
Brittle
Cleavage:
Distinct/Good
On {001}
On {001}
Fracture:
Conchoidal
Density:
5.81 g/cm3 (Calculated)
Optical Data of Cobaltneustädtelite
Type:
Biaxial (-)
RI values:
nα = 2.02 nβ = 2.09 nγ = 2.12
Max. Birefringence:
δ = 0.100
Based on recorded range of RI values above.
Based on recorded range of RI values above.
Interference Colours:
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.
Surface Relief:
Very High (positive)
Relative to Canada balsam mounting medium (n ≈ 1.537).
Relative to Canada balsam mounting medium (n ≈ 1.537).
This shows the grain boundary and Becke line effect under plane-polarised
light, based on the contrast between this mineral's average refractive
index and the mounting medium. It does not take into account mineral
colouration.
In focus
Interference Figure:
This shows the idealized biaxial acute bisectrix (Bxa) interference figure
- the conoscopic view for a grain cut perpendicular to the acute bisectrix, using
this mineral's 2V. The two small white dots mark the melatopes - the points
where the two optic axes emerge - and are shown only when they fall within the
field of view. The coloured bands are isochromatics, and the dark bands are
isogyres.
Rotate the stage: at 0°/90° the isogyres form a cross through the melatopes; at 45° they pull apart into curved hyperbolas. That splitting on rotation - absent in a uniaxial figure - is the standard diagnostic test for telling biaxial minerals from uniaxial ones. If 2V is large, the melatopes may fall outside the field of view, as they often do at the microscope too.
No measured or calculated 2V is on file for this mineral, so the value used here (65°) is estimated from its recorded refractive indices and optic sign, not from a direct 2V measurement.
Rotate the stage: at 0°/90° the isogyres form a cross through the melatopes; at 45° they pull apart into curved hyperbolas. That splitting on rotation - absent in a uniaxial figure - is the standard diagnostic test for telling biaxial minerals from uniaxial ones. If 2V is large, the melatopes may fall outside the field of view, as they often do at the microscope too.
No measured or calculated 2V is on file for this mineral, so the value used here (65°) is estimated from its recorded refractive indices and optic sign, not from a direct 2V measurement.
Dispersion:
relatively weak
Pleochroism:
Strong
Comments:
X = brown to opaque, Y = yellow, and Z = pale yellow.
Comments:
X is very near to [010]; for crystals lying on (001) X' shows an oblique extinction of approximately 7° relative to [010].
Chemistry of Cobaltneustädtelite
Mindat Formula:
Bi2Fe3+(Co,Fe3+)(AsO4)2(O,OH)4
Element Weights:
Crystallography of Cobaltneustädtelite
Crystal System:
Triclinic
Class (H-M):
1 - Pinacoidal
Space Group:
P1
Cell Parameters:
a = 9.156 Å, b = 6.148 Å, c = 9.338 Å
α = 83.24°, β = 70.56°, γ = 86.91°
α = 83.24°, β = 70.56°, γ = 86.91°
Ratio:
a:b:c = 1.489 : 1 : 1.519
Unit Cell V:
492.172 ų
Z:
2
Morphology:
Tabular parallel to {001} and slightly to distinctly elongated parallel to [010]. Also {001}, {100}, ~{011} and {201}.
Twinning:
None observed.
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 8.757 Å | (50) |
| 3.752 Å | (100) |
| 3.552 Å | (50) |
| 3.507 Å | (40) |
| 2.901 Å | (100) |
| 2.750 Å | (40) |
| 2.667 Å | (70) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 7: Great Oxidation Event | <2.4 |
| 47a : [Near-surface hydration of prior minerals] | |
| 47h : [Near-surface oxidized, dehydrated minerals] |
Type Occurrence of Cobaltneustädtelite
General Appearance of Type Material:
Crystal aggregates up to 0.3 mm and very small tabular crystals, mostly <0.1 mm.
Place of Conservation of Type Material:
Staatliches Museum für Mineralogie und Geologie, Dresden, Germany, catalogue numbers 18328 and 18329.
Associated Minerals at Type Locality:
Synonyms of Cobaltneustädtelite
Other Language Names for Cobaltneustädtelite
Related Minerals - Strunz-mindat Grouping
| 8.BK.05 | Brazilianite | NaAl3(PO4)2(OH)4 |
| 8.BK.10 | Neustädtelite | Bi2Fe3+(Fe3+,Co)(AsO4)2(O,OH)4 |
| 8.BK.10 | Medenbachite | Bi2Fe3+Cu2+(AsO4)2O(OH)3 |
| 8.BK.15 | Curetonite | Ba(Al,Ti)(PO4)(OH,O)F |
| 8.BK.20 | Heyite | Pb5Fe2+2(VO4)2O4 |
| 8.BK.25 | Jamesite | Pb2Zn(Fe2+,Zn)2Fe3+4(AsO4)4(OH)10 |
| 8.BK.25 | Lulzacite | Sr2Fe2+(Fe2+,Mg)2Al4(PO4)4(OH)10 |
| 8.BK.25 | Désorite | Pb2(Fe3+6Zn)O2(PO4)4(OH)8 |
| 8.BK.30 | Nishanbaevite | KAl2O(AsO4)(SO4) |
| 8.BK.35 | Zircarsite | Na18Cu12ZrO8(AsO4)8Cl6 |
| 8.BK.35 | Arsmirandite | Na18Cu12Fe3+O8(AsO4)8Cl5 |
| 8.BK.35 | Lebedevite | K4Na14Cu14O8(AsO4)8Cl6 |
| 8.BK.35 | Lehmannite | Na18Cu12TiO8(AsO4)8FCl5 |
Fluorescence of Cobaltneustädtelite
Not fluorescent
Other Information
Notes:
Completely soluble in warm, dilute HCl without effervescence.
Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.
Internet Links for Cobaltneustädtelite
mindat.org URL:
https://www.mindat.org/min-11015.html
Please feel free to link to this page.
Please feel free to link to this page.
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References for Cobaltneustädtelite
Reference List:
Effenberger, H., Krause, W., Bernhardt, H.-J., McCammon, C. (2000) Substitution of Fe3++O2- ⇔ Co2++(OH)- and ordering of the Bi atoms in Bi2Fe(Fe,Co)(O,OH)2(OH)2(AsO4)2 minerals neustädtelite and cobaltneustädtelite. Acta Crystallographica Section A Foundations of Crystallography, 56. doi:10.1107/s0108767300027525
Localities for Cobaltneustädtelite
Showing 6 localities.
symbol to view information about a locality.
The Locality List
- This locality has map coordinates listed.
- This locality has estimated coordinates.
ⓘ - Click for references and further information on this occurrence.
? - Indicates mineral may be doubtful at this locality.
- Good crystals or important locality for species.
- World class for species or very significant.
(TL) - Type Locality for a valid mineral species.
(FRL) - First Recorded Locality for everything else (eg varieties).
All localities listed without proper references should be considered as questionable.
Germany (TL) | |
| Krause et al. (2002) |
| Am. Min. 87:726-738 | |
| Lapis 30 (7/8) | |
| Lapis 30 (7/8) | |
| Am. Min. 87:726-738 |
Spain | |
| Schnorrer et al. (2005) |
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Güldener Falk Mine, Neustädtel, Schneeberg, Erzgebirgskreis, Saxony, Germany