Mineralogy Database

Columbite-(Mg) Mineral Data

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General Columbite-(Mg) Information

Help on Chemical  Formula: Chemical Formula: (Mg,Fe++,Mn)(Nb,Ta)2O6
Help on Composition: Composition: Molecular Weight = 330.49 gm
   Magnesium   5.15 %  Mg    8.54 % MgO
   Tantalum   10.95 %  Ta   13.37 % Ta2O5
   Titanium    2.90 %  Ti    4.83 % TiO2
   Manganese   1.66 %  Mn    2.15 % MnO
   Niobium    47.79 %  Nb   68.36 % Nb2O5
   Aluminum    0.82 %  Al    1.54 % Al2O3
   Iron        1.69 %  Fe    2.17 % FeO
   Oxygen     29.05 %  O
             ______        ______ 
             100.00 %      100.97 % = TOTAL OXIDE
Help on Empirical Formula: Empirical Formula: Mg0.7Fe2+0.1Mn2+0.1Al0.1Nb1.7Ti0.2Ta0.2O6
Help on Environment: Environment: In a pegmatite in partially assimilated dolomitic marbles.
Help on IMA Status: IMA Status: Approved IMA 1963
Help on Locality: Locality: Kukhi-Lal deposit, southwestern Pamir Mountains, Tadzhikistan. Link to MinDat.org Location Data.
Help on Name Origin: Name Origin: Named for the dominent MAGNESIum and its relationship to ferrocolumbite (formerly columbite).
Help on Name Pronunciation: Name Pronunciation: Columbite-(Mg) + Pronunciation Say COLUMBITE-(MG)
Help on Synonym: Synonym: IMA2002-D
  Magnesiocolumbite - Renamed to Columbite-(Mg) by Mineralogical Record, v39 (2008), p 131
  Magnocolumbite
  Toddite
 

Columbite-(Mg) Crystallography

Help on Axial Ratios: Axial Ratios: a:b:c =0.3542:1:0.3987
Help on Cell Dimensions: Cell Dimensions: a = 5.02, b = 14.17, c = 5.65, Z = 4; V = 401.90 Den(Calc)= 5.46
Help on Crystal System: Crystal System: Orthorhombic - Dipyramidal H-M Symbol (2/m 2/m 2/m) Space Group: Pcan
Help on X Ray Diffraction: X Ray Diffraction: By Intensity(I/Io): 2.955(1), 1.535(0.9), 1.723(0.9),
 

Physical Properties of Columbite-(Mg)

Help on Cleavage: Cleavage: {010} Indistinct, {100} Indistinct
Help on Color: Color: Brownish black, Black.
Help on Density: Density: 5.04
Help on Diaphaneity: Diaphaneity: Opaque
Help on Fracture: Fracture: Sub Conchoidal - Fractures developed in brittle materials characterized by semi-curving surfaces.
Help on Habit: Habit: Acicular - Occurs as needle-like crystals.
Help on Habit: Habit: Tabular - Form dimensions are thin in one direction.
Help on Hardness: Hardness: 6.5 - Pyrite
Help on Luminescence: Luminescence: Non-fluorescent.
Help on Luster: Luster: Sub Metallic
Help on Streak: Streak: dark brown
 

Optical Properties of Columbite-(Mg)

Help on Gladstone-Dale: Gladstone-Dale: CI meas= -0.091 (Poor) - where the CI = (1-KPDmeas/KC)
CI calc= -0.007 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2527,KPDmeas= 0.2738,KC= 0.251
Ncalc = 2.26 - 2.37
Help on Optical Data: Optical Data: Biaxial (-), a=2.33-2.36, g=2.39-2.44, bire=0.0600-0.0800
Help on Pleochroism (x): Pleochroism (x): brownish yellow.
Help on Pleochroism (z): Pleochroism (z): brownish red.
 

Calculated Properties of Columbite-(Mg)

Help on Electron Density: Electron Density: Bulk Density (Electron Density)=5.01 gm/cc
note: Specific Gravity of Columbite-(Mg) =5.46 gm/cc.
Help on Fermion Index: Fermion Index: Fermion Index = 0.0094051723
Boson Index = 0.9905948277
Help on Photoelectric: Photoelectric: PEColumbite-(Mg) = 198.31 barns/electron
U=PEColumbite-(Mg) x rElectron Density= 992.68 barns/cc.
Help on Radioactivity: Radioactivity: GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Columbite-(Mg) is Not Radioactive
 

Columbite-(Mg) Classification

Help on  Dana Class: Dana Class: 08.03.02.05 (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
Help on  Strunz Class: 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 Columbite-(Mg) Information

Help on References: References: NAME( AntBidBlaNic3) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(AntBidBlaNic3)
Help on See Also: See Also: Links to other databases for Columbite-(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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Print or Cut-and-Paste your Columbite-(Mg) Specimen Label here :

Columbite-(Mg)

(Mg,Fe++,Mn)(Nb,Ta)2O6
Dana No: 08.03.02.05 Strunz No: 04.DB.35
Locality:

 

Notes:

 

 
   
 


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