Tantalite

Tantalite
Tantalite
	Tantalite, Pilbara district, Australia
General
Category	Oxide minerals
Formula; (repeating unit)	(Fe,Mn)Ta2O6
IMA symbol	Ttl
Strunz classification	4.DB.35
Crystal system	Orthorhombic
Crystal class	Dipyramidal (mmm) ; H-M symbol: (2/m 2/m 2/m)
Space group	Pbcn (no. 60)
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, a corrosion (heat and acid) resistant metal. 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).^[3] 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 the same chemical composition, but different crystal symmetry: orthorhombic for tantalite and tetragonal for tapiolite.^[4]

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

^ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
^ "TANTALITE (Iron Manganese Tantalum Niobium Oxide)". Galleries.com. Retrieved 2011-10-25.
^ ^a ^b Tantalite. Mindat.org (2011-09-07). Retrieved on 2011-10-30.
^ P. Cerny; et al. (1992). "The tantalite-tapiolite gap: natural assemblages versus experimental data" (PDF). Canadian Mineralogist. 30: 587.

[1] Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.

[2] "TANTALITE (Iron Manganese Tantalum Niobium Oxide)". Galleries.com. Retrieved 2011-10-25.

[Mindat-3] Tantalite. Mindat.org (2011-09-07). Retrieved on 2011-10-30.

[4] P. Cerny; et al. (1992). "The tantalite-tapiolite gap: natural assemblages versus experimental data" (PDF). Canadian Mineralogist. 30: 587.

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