General Ferrocolumbite Information
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Chemical Formula: |
Fe++Nb2O6 |
Composition: |
Molecular Weight = 337.66 gm |
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Niobium 55.03 % Nb 78.72 % Nb2O5 |
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Iron 16.54 % Fe 21.28 % FeO |
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Oxygen 28.43 % O |
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______ ______ |
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100.00 % 100.00 % = TOTAL OXIDE |
Empirical Formula: |
Fe2+Nb2O6 |
Environment: |
Pegmatites, and alluvial deposits. |
IMA Status: |
Valid Species (Pre-IMA) 1802 |
Locality: |
M'buye Mine, Rwanda. Link to MinDat.org Location Data. |
Name Origin: |
Named after its content of the element niobium, formerly called columbium and the Latin ferrium - "iron." |
Synonym: |
Coltan |
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Columbite |
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Columbite-Tantalite |
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ICSD 71052 |
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Niobite |
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PDF 33-659 |
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Ferrocolumbite Image |
Images:
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Ferrocolumbite Microcline
Comments: Blocky, dark brown ferrocolumbite on pale greenish blue amazonite (microcline).
Location: Crystal Park, El Paso Co., Colorado, USA.
Scale: 2.5 x 1.5 cm.
© Fabre Minerals |
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Images:
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Images:
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Ferrocolumbite Crystallography
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Axial Ratios: |
a:b:c =0.4015:1:0.3546 |
Cell Dimensions: |
a = 5.746, b = 14.308, c = 5.075, Z = 4; V = 417.23 Den(Calc)= 5.38 |
Crystal System: |
Orthorhombic - DipyramidalH-M Symbol (2/m 2/m 2/m) Space Group: Pcan |
X Ray Diffraction: |
By Intensity(I/Io): 2.977(1), 3.675(0.4), 1.726(0.16), |
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Crystal Structure:
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Wenger M , Armbruster T , Geiger C A , American Mineralogist , 76 (1991) p.1897-1904, Cation distribution in partially ordered columbite from the Kings Mountain, pegmatite, North Carolina, sample NCP5, T = 100 K
View Additional jPOWD Structure files for Ferrocolumbite
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Physical Properties of Ferrocolumbite
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Cleavage: |
[010] Distinct |
Color: |
Black, Brownish black. |
Density: |
5.3 - 7.3, Average = 6.3 |
Diaphaniety: |
Translucent to opaque |
Fracture: |
Sub Conchoidal - Fractures developed in brittle materials characterized by semi-curving surfaces. |
Habit: |
Massive - Granular - Common texture observed in granite and other igneous rock. |
Habit: |
Striated - Parallel lines on crystal surface or cleavage face. |
Hardness: |
6 - Orthoclase |
Luminescence: |
Non-fluorescent. |
Luster: |
Sub Metallic |
Streak: |
blackish brown |
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Optical Properties of Ferrocolumbite
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Gladstone-Dale: |
CI meas= 0.149 (Poor) - where the CI = (1-KPDmeas/KC) CI calc= 0.004 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.25,KPDmeas= 0.2135,KC= 0.251 |
Optical Data: |
Biaxial (+), b=2.29-2.4 |
RL Color: |
Grayish white with a brownish tint and reddish internal reflections. |
Reflectivity |
Standardized Intensity (100%) Reflection Spectra of Ferrocolumbite in Air
| λ |
R1 |
R2 |
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∑ R1(λ) |
∑ R2(λ) |
| 400 nm |
18.40 |
19.10 |

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| 420 nm |
17.70 |
18.60 |

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| 440 nm |
17.30 |
18.20 |

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| 460 nm |
17.10 |
17.90 |

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| 480 nm |
16.90 |
17.70 |

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| 500 nm |
16.90 |
17.60 |

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| 520 nm |
16.80 |
17.50 |

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| 540 nm |
16.80 |
17.40 |

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| 560 nm |
16.70 |
17.30 |

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| 580 nm |
16.70 |
17.20 |

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| 600 nm |
16.70 |
17.20 |

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| 620 nm |
16.60 |
17.10 |

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| 640 nm |
16.50 |
17.10 |

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| 660 nm |
16.40 |
16.90 |

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| 680 nm |
16.30 |
16.80 |

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| 700 nm |
16.10 |
16.80 |

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Calculated Relative Intensity Colors of Ferrocolumbite in Air
Relative Intensity |
0% |
60% |
100% |
120% |
180% |
240% |
300% |
360% |
420% |
480% |
530% |
| R1 |
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| R2 |
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Calculated Properties of Ferrocolumbite
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Electron Density: |
relectron=4.97 gm/cc note: rFerrocolumbite =5.38 gm/cc. |
Fermion Index |
Fermion Index = 0.00364 Boson Index = 0.99636 |
Photoelectric: |
PEFerrocolumbite = 89.38 barns/electron U=PEFerrocolumbite x relectron= 444.33 barns/cc. |
Radioactivity: |
GRapi = 0 (Gamma Ray American Petroleum Institute Units) Ferrocolumbite is Not Radioactive |
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Ferrocolumbite Classification
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Dana Class: |
8.3.2.2 (8)Multiple Oxides with Nb, Ta, and Ti |
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(8.3)where A (B2O6) |
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(8.3.2)Dana Group |
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8.3.2.1 Ferrotantalite FeTa2O6 Pcan 2/m 2/m 2/m |
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8.3.2.2 Ferrocolumbite FeNb2O6 Pcan 2/m 2/m 2/m |
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8.3.2.3 Manganotantalite MnTa2O6 Pcan 2/m 2/m 2/m |
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8.3.2.4 Manganocolumbite (Mn,Fe)(Nb,Ta)2O6 Pcan 2/m 2/m 2/m |
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8.3.2.5 Magnesiocolumbite (Mg,Fe,Mn)(Nb,Ta)2O6 Pcan 2/m 2/m 2/m |
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8.3.2.6 Magnesiotantalite! (Mg,Fe)(Ta,Nb)2O6 P bcn 2/m 2/m 2/m |
Strunz Class: |
IV/D.18-30 IV - Oxides |
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IV/D - Oxides with metal : oxygen = 1:2 (MO2 and related compounds) |
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IV/D.18 - Columbite series |
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IV/D.18-10 Magnesiocolumbite (Mg,Fe,Mn)(Nb,Ta)2O6 Pcan 2/m 2/m 2/m |
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IV/D.18-20 Manganocolumbite (Mn,Fe)(Nb,Ta)2O6 Pcan 2/m 2/m 2/m |
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IV/D.18-30 Ferrocolumbite FeNb2O6 Pcan 2/m 2/m 2/m |
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IV/D.18-35 Magnesiotantalite! (Mg,Fe)(Ta,Nb)2O6 P bcn 2/m 2/m 2/m |
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IV/D.18-40 Manganotantalite MnTa2O6 Pcan 2/m 2/m 2/m |
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IV/D.18-50 Ferrotantalite FeTa2O6 Pcan 2/m 2/m 2/m |
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Other Ferrocolumbite Information
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References: |
NAME( Duda&Rejl90) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(AntBidBlaNic1) |
See Also: |
Links to other databases for Ferrocolumbite :
1 - Alkali-Nuts(English)
2 - Alkali-Nuts(Francais)
3 -Am. Min. Crystal Structure Database
4 -Athena
5 - Crocoite.com Mineral Locations
6 - EUROmin Project
7 -Google Images
8 -Google Scholar
9 -Handbook of Mineralogy (UofA)
10 -MinDAT
11 -MinMax(Deutsch)
12 -MinMax(English)
13 -Mineralienatlas (Deutsch)
14 - Philatelic Mineralogy
15 -QUT Mineral Atlas
16 -École des Mines de Paris
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Print or Cut-and-Paste your Ferrocolumbite Specimen Label here :
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Ferrocolumbite
Fe++Nb2O6
Dana No: 8.3.2.2 Strunz No: IV/D.18-30
Locality:
Notes:
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