Tantalite-(Mg) Mineral Data

General Tantalite-(Mg) Information

Chemical Formula:

(Mg,Fe)(Ta,Nb)2O6

Composition:

Molecular Weight = 425.25 gm

Magnesium 3.20 % Mg 5.31 % MgO

Tantalum 51.06 % Ta 62.35 % Ta₂O₅

Titanium 0.23 % Ti 0.38 % TiO₂

Manganese 0.65 % Mn 0.83 % MnO

Niobium 17.04 % Nb 24.38 % Nb₂O₅

Iron 5.25 % Fe 6.76 % FeO

Oxygen 22.57 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Mg_0.56Fe²⁺_0.4Mn²⁺_0.05Ta_1.2Nb_0.78Ti_0.02O₆

Environment:

Intergrown with ferrotantalie, ferrocolumbite as replacement rims on manganotantilite crystals in a de-silicified granitic pegmatite. Columbite-tantalite group.

IMA Status:

Approved IMA 2003 (Dana # Added)

Locality:

Lipovka pegmatite field, Rezh district, Central Urals, Russia. Link to MinDat.org Location Data.

Name Origin:

Named as the magnesium-dominant member of the tantalite series.

Synonym:

IMA2002-018

Magnesiotantalite - Renamed to Tantalite-(Mg) by Mineralogical Record, v39 (2008), p 131

Tantalite-(Mg) Crystallography

Axial Ratios:

a:b:c =2.503:1:0.8819

Cell Dimensions:

a = 14.355, b = 5.735, c = 5.058, Z = 4; V = 416.40 Den(Calc)= 6.78

Crystal System:

Orthorhombic - Dipyramidal H-M Symbol (2/m 2/m 2/m) Space Group: P bcn

$Help on X Ray Diffraction:$ X Ray Diffraction:

By Intensity(I/I_o): 2.96(1)(311), 1.462(0.9)(332), 1.728(0.7)(621),1.105(0.6), 1.196(0.6), 1.774(0.6)(330), 3.67(0.6)(310,111),

Physical Properties of Tantalite-(Mg)

Cleavage:

None

Color:

Black.

Density:

6.7

Diaphaneity:

Opaque

Fracture:

Brittle - Uneven - Very brittle fracture producing uneven fragments.

Habit:

Irregular Grains - Occurs as splotchy, anhedral crystals forming inclusions in other minerals or rocks.

Hardness:

5.5 - Knife Blade

Luster:

Sub Metallic

Streak:

brown red

Optical Properties of Tantalite-(Mg)

Optical Data:

NCalc= 2.26 - from Gladstone-Dale relationship (KC = 0.1859) where Ncalc=Dcalc*KC+1
NCalc= 2.25 - from Gladstone-Dale relationship (KC = 0.1859) where Ncalc=Dmeas*KC+1

RL Anisotrophism:

Weak.

RL Bireflectance:

Very weak.

RL Color:

Light gray with brownish red internal reflections in air.

Reflectivity

**Standardized Intensity (100%) Reflection Spectra of Tantalite-(Mg) in Air**
λ	R₁	R₂	∑ R₁(λ)	∑ R₂(λ)
400 nm	15.20	14.02
410 nm	15.18	13.69
420 nm	15.05	13.49
430 nm	14.79	13.27
440 nm	14.73	12.95
450 nm	14.28	12.76
460 nm	13.97	12.82
470 nm	13.75	12.95
480 nm	13.58	13.05
490 nm	13.44	13.13
500 nm	13.33	13.20
510 nm	13.25	13.22
520 nm	13.23	13.19
530 nm	13.25	13.18
540 nm	13.33	13.20
546 nm	13.14	13.19
550 nm	13.47	13.28
560 nm	13.67	13.45
570 nm	13.94	13.67
580 nm	14.25	13.94
589 nm	14.57	14.24
590 nm	14.58	14.25
600 nm	14.90	14.58
610 nm	15.18	14.90
620 nm	15.41	15.16
630 nm	15.56	15.32
640 nm	15.61	15.31
650 nm	15.55	15.15
660 nm	15.41	14.83
670 nm	15.22	14.48
680 nm	15.00	14.12
690 nm	14.88	13.97
700 nm	14.76	13.76

**Calculated Relative Intensity Colors of Tantalite-(Mg) in Air**
Relative Intensity	0%	70%	100%	140%	210%	280%	350%	420%	490%	560%	630%	670%
R₁
R₂

Calculated Properties of Tantalite-(Mg)

Electron Density:

Bulk Density (Electron Density)=5.94 gm/cc
note: Specific Gravity of Tantalite-(Mg) =6.78 gm/cc.

Fermion Index:

Fermion Index = 0.0047750531
Boson Index = 0.9952249469

Photoelectric:

PE_{Tantalite-(Mg)}= 629.35 barns/electron
U=PE_{Tantalite-(Mg)} x rElectron Density=3,740.45 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Tantalite-(Mg) is Not Radioactive

Tantalite-(Mg) Classification

Dana Class:

08.03.02.06 (08)Multiple Oxides with Nb, Ta, and Ti

(08.03)where A (B2O6)

(08.03.02)Tantalite - Columbite Series

08.03.02.01 Tantalite-(Fe) FeTa2O6 Pcan 2/m 2/m 2/m

08.03.02.02 Columbite-(Fe) FeNb2O6 Pcan 2/m 2/m 2/m

08.03.02.03 Tantalite-(Mn) MnTa2O6 Pcan 2/m 2/m 2/m

08.03.02.04 Columbite-(Mn) (Mn,Fe)(Nb,Ta)2O6 Pcan 2/m 2/m 2/m

08.03.02.05 Columbite-(Mg) (Mg,Fe,Mn)(Nb,Ta)2O6 Pcan 2/m 2/m 2/m

08.03.02.06 Tantalite-(Mg)! (Mg,Fe)(Ta,Nb)2O6 P bcn 2/m 2/m 2/m

Strunz Class:

04.DB.35 04 - OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodate

04.D - Metal:Oxygen = 1:2 and similar

04.DB -With medium-sized cations; chains of edge-sharing octahedra

04.DB.35 Columbite-(Mg) (Mg,Fe,Mn)(Nb,Ta)2O6 Pcan 2/m 2/m 2/m

04.DB.35 Tantalite-(Fe) FeTa2O6 Pcan 2/m 2/m 2/m

04.DB.35 Columbite-(Fe) FeNb2O6 Pcan 2/m 2/m 2/m

04.DB.35 Columbite-(Mn) (Mn,Fe)(Nb,Ta)2O6 Pcan 2/m 2/m 2/m

04.DB.35 Qitianlingite Fe2Nb2WO10 P bcn 2/m 2/m 2/m

04.DB.35 Tantalite-(Mn) MnTa2O6 Pcan 2/m 2/m 2/m

04.DB.35 Tantalite-(Mg)! (Mg,Fe)(Ta,Nb)2O6 P bcn 2/m 2/m 2/m

Other Tantalite-(Mg) Information

References:

NAME( AmMin, 89:468) PHYS. PROP.(AmMin, 89:468) OPTIC PROP.(MinRec, 35:357)

See Also:

Links to other databases for Tantalite-(Mg) :
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

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Tantalite-(Mg)

(Mg,Fe)(Ta,Nb)2O6
Dana No: 08.03.02.06 Strunz No: 04.DB.35
Locality:

Notes:

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