Magnesiotantalite Mineral Data

Magnesiotantalite Mineral Data

General Magnesiotantalite 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

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Magnesiotantalite 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 - DipyramidalH-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 Magnesiotantalite

Cleavage:

None

Color:

Black.

Density:

6.7

Diaphaniety:

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 Magnesiotantalite

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 Magnesiotantalite 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 Magnesiotantalite in Air**
Relative Intensity	0%	70%	100%	140%	210%	280%	350%	420%	490%	560%	630%	670%
R₁
R₂

Calculated Properties of Magnesiotantalite

Electron Density:

r_electron=5.94 gm/cc
note: r_{Magnesiotantalite}=6.78 gm/cc.

Fermion Index

Fermion Index = 0.00477
Boson Index = 0.99523

Photoelectric:

PE_{Magnesiotantalite}= 629.35 barns/electron
U=PE_{Magnesiotantalite} x r_electron=3,740.44 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Magnesiotantalite is Not Radioactive

Magnesiotantalite Classification

Dana Class:

8.3.2.6 (8)Multiple Oxides with Nb, Ta, and Ti

(8.3)where A (B2O6)

(8.3.2)Dana Group

8.3.2.1 Ferrotantalite FeTa2O6 Pcan 2/m 2/m 2/m

8.3.2.2 Ferrocolumbite FeNb2O6 Pcan 2/m 2/m 2/m

8.3.2.3 Manganotantalite MnTa2O6 Pcan 2/m 2/m 2/m

8.3.2.4 Manganocolumbite (Mn,Fe)(Nb,Ta)2O6 Pcan 2/m 2/m 2/m

8.3.2.5 Magnesiocolumbite (Mg,Fe,Mn)(Nb,Ta)2O6 Pcan 2/m 2/m 2/m

8.3.2.6 Magnesiotantalite ! (Mg,Fe)(Ta,Nb)2O6 P bcn 2/m 2/m 2/m

Strunz Class:

IV/D.18-35 IV - Oxides

IV/D - Oxides with metal : oxygen = 1:2 (MO2 and related compounds)

IV/D.18 - Columbite series

IV/D.18-10 Magnesiocolumbite (Mg,Fe,Mn)(Nb,Ta)2O6 Pcan 2/m 2/m 2/m

IV/D.18-20 Manganocolumbite (Mn,Fe)(Nb,Ta)2O6 Pcan 2/m 2/m 2/m

IV/D.18-30 Ferrocolumbite FeNb2O6 Pcan 2/m 2/m 2/m

IV/D.18-35 Magnesiotantalite (Mg,Fe)(Ta,Nb)2O6 P bcn 2/m 2/m 2/m

IV/D.18-40 Manganotantalite MnTa2O6 Pcan 2/m 2/m 2/m

IV/D.18-50 Ferrotantalite FeTa2O6 Pcan 2/m 2/m 2/m

Other Magnesiotantalite Information

References:

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

See Also:

Links to other databases for Magnesiotantalite :
1 -Am. Min. Crystal Structure Database 2 -Athena 3 -Google Images 4 -Google Scholar 5 -Handbook of Mineralogy (UofA) 6 -MinDAT 7 -MinMax(Deutsch) 8 -MinMax(English) 9 -Mineralienatlas (Deutsch) 10 -QUT Mineral Atlas

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Magnesiotantalite

(Mg,Fe)(Ta,Nb)2O6
Dana No: 8.3.2.6 Strunz No: IV/D.18-35
Locality:

Notes: