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Nancyrossite
A valid IMA mineral species - pending publication
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Formula:
FeGeO6H5
Specific Gravity:
3.842 (Calculated)
Crystal System:
Tetragonal
Name:
The mineral honours Prof. Nancy L. Ross, mineral physicist and mineralogist at Virginia Polytechnic Institute, Blacksburg, Virginia, USA. Nancy Ross has made major contributions to our knowledge of the crystal chemistry, thermochemistry and crystallography of perovskites and related phases, including stottite.
Isostructural with:
Germanium analogue of jeanbandyite.
It is from the germanium horizon at Level 30 of the Tsumeb mine.
It is from the germanium horizon at Level 30 of the Tsumeb mine.
Unique Identifiers
Mindat ID:
471423
Long-form identifier:
mindat:1:1:471423:7
IMA Classification of Nancyrossite
Approved, Pending publication
IMA Formula:
Fe3+GeO6H5
Classification of Nancyrossite
4.FC.15
4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
F : Hydroxides (without V or U)
C : Hydroxides with OH, without H2O; corner-sharing octahedra
4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
F : Hydroxides (without V or U)
C : Hydroxides with OH, without H2O; corner-sharing octahedra
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 |
|---|---|---|
| Ncy | 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 Nancyrossite
Density:
3.842 g/cm3 (Calculated)
Optical Data of Nancyrossite
Type:
Biaxial (-)
RI values:
nα = 1.966 nβ = 1.971 nγ = 1.974
2V:
Measured: 73.5° (4), Calculated: 75.4°
Max. Birefringence:
δ = 0.008
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.
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.
Dispersion:
r < v slight
Pleochroism:
Non-pleochroic
Comments:
calculated
Chemistry of Nancyrossite
Mindat Formula:
FeGeO6H5
Element Weights:
Elements listed:
Crystallography of Nancyrossite
Crystal System:
Tetragonal
Class (H-M):
4/m - Dipyramidal
Space Group:
P42/n
Cell Parameters:
a = 7.3738(1) Å, c = 7.2970(2) Å
Ratio:
a:c = 1 : 0.99
Unit Cell V:
396.76 ų (Calculated from Unit Cell)
Z:
4
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 3.688 Å | (100) |
| 3.649 Å | (31) |
| 2.594 Å | (53) |
| 1.844 Å | (29) |
| 1.650 Å | (31) |
| 1.646 Å | (37) |
| 1.635 Å | (38) |
| 1.503 Å | (36) |
Type Occurrence of Nancyrossite
General Appearance of Type Material:
occurs as subhedral grains or fragments up to 0.3 mm maximum dimension, that do not display stepped surfaces (stottite)
Place of Conservation of Type Material:
Type material is deposited in the collections of the Natural History Museum, Cromwell Road, London, SW7 5BD UK, catalogue numbers BM2024,1, BM2024,2, and BM2024,3
Geological Setting of Type Material:
likely formed by the oxidation and partial dehydrogenation of stottite,
Associated Minerals at Type Locality:
Other Language Names for Nancyrossite
Dutch:Nancyrossiet
German:Nancyrossit
Relationship of Nancyrossite to other Species
Other Members of Stottite Subgroup:
| Mopungite | Na[Sb5+(OH)6] | Tet. 4/m : P42/n |
| Stottite | Fe2+[Ge4+(OH)6] | Tet. 4/m : P42/n |
| Tetrawickmanite | Mn2+[Sn4+(OH)6] | Tet. 4/m : P42/n |
| Zincostottite | ZnGe(OH)6 | Tet. 4/m : P42/n |
Related Minerals - Strunz-mindat Grouping
| 4.FC.05 | Dzhalindite | In(OH)3 |
| 4.FC.05 | Bernalite | Fe(OH)3 · nH2O (n = 0.0 to 0.25) |
| 4.FC.05 | Söhngeite | Ga(OH)3 |
| 4.FC.10 | Mushistonite | (Cu,Zn,Fe2+)[Sn(OH)6] |
| 4.FC.10 | Natanite | Fe2+[Sn(OH)6] |
| 4.FC.10 | Burtite | Ca[Sn(OH)6] |
| 4.FC.10 | Vismirnovite | Zn[Sn(OH)6] |
| 4.FC.10 | Wickmanite | Mn2+[Sn(OH)6] |
| 4.FC.10 | Schoenfliesite | Mg[Sn(OH)6] |
| 4.FC.15 | Jeanbandyite | Fe3+Sn(OH)5O |
| 4.FC.15 | Tetrawickmanite | Mn2+[Sn4+(OH)6] |
| 4.FC.15 | Zincostottite | ZnGe(OH)6 |
| 4.FC.15 | Stottite | Fe2+[Ge4+(OH)6] |
| 4.FC.15 | Mopungite | Na[Sb5+(OH)6] |
| 4.FC.20 | Ferronigerite-2N1S | (Al,Fe,Zn)2(Al,Sn)6O11(OH) |
| 4.FC.20 | Magnesionigerite-6N6S | (Mg,Al,Zn)3(Al,Sn,Fe)8O15(OH) |
| 4.FC.20 | Magnesionigerite-2N1S | (Mg,Al,Zn)2(Al,Sn)6O11(OH) |
| 4.FC.20 | Ferronigerite-6N6S | (Al,Fe,Zn)3(Al,Sn,Fe)8O15(OH) |
| 4.FC.20 | Zinconigerite-2N1S | (Zn,Al,Mg)2(Al,Sn)6O11(OH) |
| 4.FC.20 | Zinconigerite-6N6S | Zn3Sn2Al16O30(OH)2 |
| 4.FC.25 | Magnesiotaaffeite-6N’3S | Mg2BeAl6O12 |
| 4.FC.25 | Magnesiotaaffeite-2N’2S | Mg3Al8BeO16 |
| 4.FC.25 | Ferrotaaffeite-2N’2S | Be(Fe,Mg,Zn)3Al8O16 |
Other Information
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 Nancyrossite
mindat.org URL:
https://www.mindat.org/min-471423.html
Please feel free to link to this page.
Please feel free to link to this page.
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References for Nancyrossite
Localities for Nancyrossite
Showing 1 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.
Namibia (TL) | |
| Welch et al. (2024) |
