Tantalite

Tantalite
Tantalite

Tantalite, Pilbara district, Australia
General
Category Oxide minerals
Chemical formula (Mg,Fe)(Ta,Nb)2O6
Strunz classification 04.DB.35
Identification
Color Dark black, iron-black to dark brown, reddish brow
Crystal system Orthorhombic
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 [1][2]
Manganotantalite from Alto do Giz, RN, Brazil

Tantalite, [(Fe,Mn)(Ta,Nb)2O6], is a mineral group that is close to columbite. 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).[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.[3]

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

Contents

Occurrence

Tantalite has been found in Egypt, Namibia, Nigeria, Canada, Madagascar, northern Europe, and Maine, California, Colorado and Virginia in the United States. Brazil has the world's largest reserve of tantalite (52.1%).[4] As at 2006, 75% of world tantalite production comes from Australia.[4]

Tantalite is also mined in Guainía and Vichada, Colombia.

Sustainability

The mining of tantalite causes many ecological and social problems in Democratic Republic of Congo.[5][6]

References

  1. ^ "TANTALITE (Iron Manganese Tantalum Niobium Oxide)". Galleries.com. http://www.galleries.com/Tantalite. Retrieved 2011-10-25. 
  2. ^ a b Tantalite. Mindat.org (2011-09-07). Retrieved on 2011-10-30.
  3. ^ P. Cerny et al. (1992). "The tantalite-tapiolite gap: natural assemblages versus experimental data". Canadian Mineralogist 30: 587. http://rruff.geo.arizona.edu/doclib/cm/vol30/CM30_587.pdf. 
  4. ^ a b Papp, John F. (2006). "2006 Minerals Yearbook Nb & Ta". US Geological Survey. http://minerals.usgs.gov/minerals/pubs/commodity/niobium/#pubs. Retrieved 2008-06-03. 
  5. ^ Coltan, Gorillas and cellphones. Cellular-news.com (2001-04-03). Retrieved on 2011-10-30.
  6. ^ The Coltan Scandal. Geology.about.com (2010-07-04). Retrieved on 2011-10-30.

External links

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