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Ferrotantalite

Tantalite
Tantalite.jpg
Tantalite, Pilbara district, Australia
General
Category Oxide minerals
Formula
(repeating unit)
(Fe,Mn)Ta2O6
Strunz classification 4.DB.35
Crystal system Orthorhombic
Crystal class Dipyramidal (mmm)
H-M symbol: (2/m 2/m 2/m)
Identification
Color Dark black, iron-black to dark brown, reddish brown
Cleavage Good in one direction
Fracture Subconchoidal
Mohs scale hardness 6-6.5
Luster Submetallic to almost resinous
Streak Brownish-red to black
Specific gravity 8.0+
References

The mineral group tantalite [(Fe, Mn)Ta2O6] is the primary source of the chemical element tantalum. It is chemically similar to columbite, and the two are often grouped together as a semi-singular mineral called coltan or "columbite-tantalite" in many mineral guides. However, tantalite has a much greater specific gravity than columbite (8.0+ compared to columbite's 5.2). Iron-rich tantalite is the mineral tantalite-(Fe) or ferrotantalite and manganese-rich is tantalite-(Mn) or manganotantalite.

Tantalite is also very close to tapiolite. Those minerals have same chemical composition, but different crystal symmetry orthorhombic for tantalite and tetragonal for tapiolite.

Tantalite is black to brown in both color and streak. Manganese-rich tantalites can be brown and translucent.

Tantalite occurs in granitic pegmatites that are rich in rare-earth elements, and in placer deposits derived from such rocks. It has been found in Australia, Brazil, Canada, Colombia (Guainía and Vichada), Egypt, northern Europe, Madagascar, Namibia, Nigeria, Rwanda, the United States (California, Colorado, Maine, and Virginia), and Zimbabwe. Brazil has the world's largest reserve of tantalite (52.1%). In 2006, 75% of world tantalite production came from Australia.


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