Ashanite

Formula:

(Nb,Ta,U,Fe,Mn)

System:

Orthorhombic

Colour:

Dark brown to ...

Lustre:

Resinous, Sub-Metallic

Hardness:

5½ - 6½

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

Classification of Ashanite

IMA status:

Discredited

Hey's CIM Ref.:

18.3.8

18 : Niobates and Tantalates
3 : Niobates and tantalates containing U but not rare earths

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http://www.mindat.org/min-387.html
Please feel free to link to this page.

Physical Properties of Ashanite

Lustre:

Resinous, Sub-Metallic

Diaphaneity (Transparency):

Opaque

Colour:

Dark brown to pitch-black; brownish red in thin section

Streak:

Brown

Hardness (Mohs):

5½ - 6½

Hardness (Vickers):

VHN₁₀₀=570 - 851

Fracture:

Conchoidal, Sub-Conchoidal

Density (measured):

6.61 g/cm³

Density (calculated):

6.6 g/cm³

Crystallography of Ashanite

Crystal System:

Orthorhombic

Class (H-M):

mmm (2/m 2/m 2/m) - Dipyramidal

Space Group:

Pban {P2/b 2/a 2/n}

Cell Parameters:

a = 5.869Å, b = 4.873Å, c = 5.216Å

Ratio:

a:b:c = 1.204 : 1 : 1.07

Unit Cell Volume:

V 149.18 Å³ (Calculated from Unit Cell)

Morphology:

Single crystals are mentioned, but the habit is not stated.

X-Ray Powder Diffraction:

d-spacing		Intensity
2.95		(10)
3.65		(5)
2.54		(3)
2.51		(3)
2.38		(3)
1.729		(3)

Comments:

Recorded on type material

Optical Data of Ashanite

Type:

Biaxial (+)

RI values:

n_α = 2.310 n_β = 2.350 n_γ = 2.400

2V:

Measured: 70° to 75°, Calculated: 86°

Maximum Birefringence:

δ = 0.090

Chart shows birefringence interference colour range (at 30µm thickness) and does not take into account mineral colouration.

Surface Relief:

Very High

Dispersion:

none

Reflectivity:

440 nm	R₁=12.1%	R₂= 12.1%
460 nm	R₁=11.4%	R₂= 11.5%
480 nm	R₁=11.2%	R₂= 11.3%
500 nm	R₁=11.0%	R₂= 11.0%
520 nm	R₁=11.0%	R₂= 11.0%
540 nm	R₁=10.9%	R₂= 10.9%
560 nm	R₁=10.9%	R₂= 10.8%
580 nm	R₁=10.8%	R₂= 10.8%
600 nm	R₁=10.8%	R₂= 10.7%
620 nm	R₁=10.7%	R₂= 10.7%
640 nm	R₁=10.7%	R₂= 10.6%
660 nm	R₁=10.6%	R₂= 10.6%
680 nm	R₁=10.6%	R₂= 10.6%
700 nm	R₁=10.6%	R₂= 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

Chemical Properties of Ashanite

Formula:

(Nb,Ta,U,Fe,Mn)

Essential elements:

Nb, O

All elements listed in formula:

Fe, Mn, Nb, O, Ta, U

Analytical Data:

Analysis of type material

U3O8 (23.81)
Nb2O5 (36.76)
Ta2O5 (23.41)
REE2O3 (1.40)
FeO (8.25)
MnO (7.77)

sum 101.40 wt.-%

Empirical Formula:

(Nb

1.61

0.66

0.63

0.61

0.51

REE

0.07

)

=4.09

7.98

Relationship of Ashanite to other Species

18.3.1

Liandratite

U(Nb,Ta)

18.3.2

Uranmicrolite

(U,Ca,Ce)

(Ta,Nb)

(OH,F)

18.3.3

Betafite

(Ca,U)

(Ti,Nb)

(OH)

18.3.4

Plumbobetafite

(Pb,U,Ca)(Ti,Nb)

(OH,F)

18.3.5

Petscheckite

UFe(Nb,Ta)

18.3.6

Hydroxyl-petscheckite

UFe

1/3

(Nb,Ta)

(O,OH)

18.3.7

Oxy-petscheckite

UFe

2/3

(Nb,Ta)

Other Names for Ashanite

Other Languages:

German:	Ashanit
Spanish:	Ashanita

Other Information

Health Warning:

No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.

References for Ashanite

Reference List:

Zhan Rubo, Tian Huixin, Peng Zhizhong, Ma Zhesheng, Han Fengming, and Jing Zebei (1980): A new mineral - Ashanite, (Nb,Ta,U,Fe,Mn)4O8. Chinese Science Bulletin [Kexue Tongbao] 25(6), 510-514 (in English). - American Mineralogist (1981) 66, 217 (abstract).

Anthony, J. W. et al. (1997): Handbook of Mineralogy, Vol. 3, 27.