Ashanite
A discredited species name
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About Ashanite
Formula:
(Nb,Ta,U,Fe,Mn)4O8
Colour:
Dark brown to pitch-black; brownish red in thin section
Lustre:
Resinous, Sub-Metallic
Hardness:
5½ - 6½
Specific Gravity:
6.61
Crystal System:
Orthorhombic
Name:
From Altai and SHAN, Chinese for mountains, for the occurrence in the Altai Mountains, China.
Originally thought to be the Nb-dominant analogue of Ixiolite, the type material is now believed to be a mixture of several minerals including Ixiolite, Samarskite-(Y) and Uranmicrolite.
Originally reported from Koktokay (Keketuohai) Pegmatite field, Fuyun Co., Altay (Aletai) Prefecture, Ili Kazakh (Yili Hasake) Autonomous Prefecture, Xinjiang (Xinjiang-Uygur) Autonomous Region, China.
Possibly to be redefined (see Zubkova et al. 2020).
Originally reported from Koktokay (Keketuohai) Pegmatite field, Fuyun Co., Altay (Aletai) Prefecture, Ili Kazakh (Yili Hasake) Autonomous Prefecture, Xinjiang (Xinjiang-Uygur) Autonomous Region, China.
Possibly to be redefined (see Zubkova et al. 2020).
Unique Identifiers
Mindat ID:
387
Long-form identifier:
mindat:1:1:387:2
Similar Names
| Aphanite | A rock subtype | |
| Askanite | A variety of Montmorillonite | (Na,Ca)0.33(Al,Mg)2(Si4O10)(OH)2 · nH2O |
| Asmanite | A synonym of Tridymite |
IMA Classification of Ashanite
Discredited
Classification of Ashanite
18.3.8
18 : Niobates and Tantalates
3 : Niobates and tantalates containing U but not rare earths
18 : Niobates and Tantalates
3 : Niobates and tantalates containing U but not rare earths
Physical Properties of Ashanite
Resinous, Sub-Metallic
Transparency:
Opaque
Colour:
Dark brown to pitch-black; brownish red in thin section
Streak:
Brown
Hardness:
5½ - 6½ on Mohs scale
Hardness:
VHN100=570 - 851 - Vickers
Fracture:
Conchoidal, Sub-Conchoidal
Density:
6.61 g/cm3 (Measured) 6.6 g/cm3 (Calculated)
Optical Data of Ashanite
Type:
Biaxial (+)
RI values:
nα = 2.31 nβ = 2.35 nγ = 2.4
2V:
Measured: 70° to 75°, Calculated: 86°
Max. Birefringence:
δ = 0.090
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:
none
Reflectivity:
| Wavelength | R1 (%) | R2 (%) |
|---|---|---|
| 440nm | 12.1% | 12.1% |
| 460nm | 11.4% | 11.5% |
| 480nm | 11.2% | 11.3% |
| 500nm | 11.0% | 11.0% |
| 520nm | 11.0% | 11.0% |
| 540nm | 10.9% | 10.9% |
| 560nm | 10.9% | 10.8% |
| 580nm | 10.8% | 10.8% |
| 600nm | 10.8% | 10.7% |
| 620nm | 10.7% | 10.7% |
| 640nm | 10.7% | 10.6% |
| 660nm | 10.6% | 10.6% |
| 680nm | 10.6% | 10.6% |
| 700nm | 10.6% | 10.6% |
Graph shows reflectance levels at different wavelengths (in nm). Peak reflectance is 12.1%.
R1 shown in black, R2 shown in red
Colour in reflected light:
Pale bluish grey
Pleochroism:
Weak
Comments:
X = light brownish red, Z = dark brownish red; Orientation: X = b, Y = a, Z = c
Chemistry of Ashanite
Mindat Formula:
(Nb,Ta,U,Fe,Mn)4O8
Crystallography of Ashanite
Crystal System:
Orthorhombic
Class (H-M):
mmm(2/m2/m2/m) - Dipyramidal
Space Group:
Pban
Cell Parameters:
a = 5.869 Å, b = 4.873 Å, c = 5.216 Å
Ratio:
a:b:c = 1.204 : 1 : 1.07
Unit Cell V:
149.18 ų (Calculated from Unit Cell)
Z:
1
Morphology:
Single crystals are mentioned, but the habit is not stated.
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 2.95 Å | (10) |
| 3.65 Å | (5) |
| 2.54 Å | (3) |
| 2.51 Å | (3) |
| 2.38 Å | (3) |
| 1.729 Å | (3) |
| 2.874 Å | (2) |
Comments:
Recorded on type material
Other Language Names for Ashanite
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 Ashanite
mindat.org URL:
https://www.mindat.org/min-387.html
Please feel free to link to this page.
Please feel free to link to this page.
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References for Ashanite
Reference List:
Localities for Ashanite
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.
China | |
| Rubo Zhang and Fengming Han (1983) |
| Zhang Rubo et al. (1985) |
Czech Republic | |
| Pauliš P. et al. (Kutna Hora, issue 1) |
Madagascar | |
| Ranorosoa (1986) |
Romania | |
| minerals-of-the-carpathians.eu (2008) |
| Hîrtopanu (1997) +1 other reference |
Nanro Pegmatite, Gilé District, Zambezia Province, Mozambique