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Download hereGENERAL DESCRIPTION
Ferrotantalite is a ferrous iron and tantalum oxide which can be found in granitic pegmatites. It forms two series with manganotantalite and ferrocolumbite.
The crystals are generally small-sized, but crystals were found in Madagascar up to 7 cm.
This species shows opaque crystals, generally gray-black with sub-metal luster. It has a rather high density (8.2).
The deposits producing of ferrotantalite are very few but one can quote, among others, Spittal an der Drau in Austria, Upper Bear Gulch in South Dakota, USA and Nyanga in Uganda.
Te place of conservation of the type of this species is not known.
Did you know? Ferrotantalite is one of the principal ores of niobium (Nb) and tantalum (Ta). This last metal is used in the manufacture of electronic components, (mainly condensers) and for the manufacture of a variety of alloys with high melting points. Niobium, as for tantalum, and their alloys with steel, constitutes a resistant metal used in aeronautics.
HISTORY : Name given its high iron content and from "Tantale", a Greek mythology figure
Species first described in 1836 by Thomas Thomson (1773-1852), Scottisch scientist
Type-locality : Lawrence Co, South Dakota, USA
CHEMICAL FORMULA : (Fe2+,Mn2+) (Ta,Nb)2O6
CRYSTAL SYSTEM : Orthorhombic
COLOR : Brown, black, gray
DIAPHANIETY : Opaque
LUSTER : Sub-metallic to vitreous
STREAK : White
MORPHOLOGIE : Small prismatic crystals
HARDNESS : 6,0-6,5
CHEMICAL CLASS: 8,2
DENSITY : IV - Oxides and hydroxides
GROUP : Columbite
STRUNZ CLASS BEFORE 2001 : 4/D.18-50
STRUNZ CLASS AFTER 2001 : 4.DB.35
