Columbite, also called niobite, niobite-tantalite and columbate [], is a black mineral group that is an ore of niobium. It has a submetallic Lustre (mineralogy), luster and a high density and is a niobate of iron and manganese. This mineral group was first found in

Haddam, Connecticut Haddam is a town in Middlesex County, Connecticut. The population was 8,452 at the time of the 2020 census. The town was also home to the now-decommissioned Connecticut Yankee Nuclear Power Plant. History Haddam, in Middlesex County, is locate ...

, in the United States. It forms a series with the

tantalum Tantalum is a chemical element with the symbol Ta and atomic number 73. Previously known as ''tantalium'', it is named after Tantalus, a villain in Greek mythology. Tantalum is a very hard, ductile, lustrous, blue-gray transition metal that ...

-dominant analogue ferrotantalite and one with the manganese-dominant analogue manganocolumbite. The iron-rich member of the columbite group is ferrocolumbite. Some tin and tungsten may be present in the mineral. Yttrocolumbite is the yttrium-rich columbite with the formula . It is a radioactive mineral found in

Mozambique Mozambique (), officially the Republic of Mozambique ( pt, Moçambique or , ; ny, Mozambiki; sw, Msumbiji; ts, Muzambhiki), is a country located in southeastern Africa bordered by the Indian Ocean to the east, Tanzania to the north, Malawi ...

. Columbite has the same composition and crystal symmetry ( orthorhombic) as

tantalite The mineral group tantalite Fe,_manganese.html"_;"title="iron.html"_;"title="iron">Fe,_manganese">Mn)Tantalum">Ta2oxygen.html" ;"title="manganese">Mn)Tantalum.html" ;"title="iron">Fe,_manganese.html" ;"title="iron.html" ;"title="iron">Fe, manga ...

. In fact, the two are often grouped together as a semi-singular mineral series called

columbite-tantalite Coltan (short for columbite–tantalites and known industrially as tantalite) is a dull black metallic ore from which the elements niobium and tantalum are extracted. The niobium-dominant mineral in coltan is columbite (after niobium's original ...

or coltan in many mineral guides. However, tantalite has a much greater

specific gravity Relative density, or specific gravity, is the ratio of the density (mass of a unit volume) of a substance to the density of a given reference material. Specific gravity for liquids is nearly always measured with respect to water at its densest ...

than columbite, more than 8.0 compared to columbite's 5.2. Columbite is also very similar to

tapiolite Tapiolite Fe,_manganese.html"_;"title="iron.html"_;"title="iron">Fe,_manganese">Mn)( Nb,_tantalum.html"_;"title="manganese">Mn)(niobium.html"_;"title="iron">Fe,_manganese.html"_;"title="iron.html"_;"title="iron">Fe,_manganese">Mn)(niobium">Nb,_tan ...

. Those minerals have same chemical composition but different crystal symmetry: orthorhombic for columbite and

tetragonal In crystallography, the tetragonal crystal system is one of the 7 crystal systems. Tetragonal crystal lattices result from stretching a cubic lattice along one of its lattice vectors, so that the cube becomes a rectangular prism with a squar ...

for tapiolite. The largest documented single crystal of columbite consisted of plates thick measuring . Columbite contains varying amounts of

thorium Thorium is a weakly radioactive metallic chemical element with the symbol Th and atomic number 90. Thorium is silvery and tarnishes black when it is exposed to air, forming thorium dioxide; it is moderately soft and malleable and has a high ...

and

uranium Uranium is a chemical element with the symbol U and atomic number 92. It is a silvery-grey metal in the actinide series of the periodic table. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons. Uranium is weak ...

, which makes it radioactive to various degrees.

History and etymology

The occurrence of columbite in the United States was made known from a specimen presumably stemming from

John Winthrop John Winthrop (January 12, 1587/88 – March 26, 1649) was an English Puritan lawyer and one of the leading figures in founding the Massachusetts Bay Colony, the second major settlement in New England following Plymouth Colony. Winthrop led t ...

(1606–1676), first Governor of the Connecticut Colony and avid mineral collector. Amidst 600 other samples, it was donated by his namesake and grandson,

(1681–1747) to

Hans Sloane Sir Hans Sloane, 1st Baronet (16 April 1660 – 11 January 1753), was an Irish physician, naturalist, and collector, with a collection of 71,000 items which he bequeathed to the British nation, thus providing the foundation of the British Mu ...

, President of the

Royal Society The Royal Society, formally The Royal Society of London for Improving Natural Knowledge, is a learned society and the United Kingdom's national academy of sciences. The society fulfils a number of roles: promoting science and its benefits, re ...

of London, upon becoming a

Fellow of the Royal Society Fellowship of the Royal Society (FRS, ForMemRS and HonFRS) is an award granted by the judges of the Royal Society of London to individuals who have made a "substantial contribution to the improvement of natural knowledge, including mathemat ...

in 1737. In 1801

Charles Hatchett Charles Hatchett FRS FRSE (2 January 1765 – 10 March 1847) was an English mineralogist and analytical chemist who discovered the element niobium, for which he proposed the name "columbium". Hatchett was elected a Fellow of the Linnaean Soci ...

discovered the element niobium in this specimen, which he named columbium in honour of explorer

Christopher Columbus Christopher Columbus * lij, Cristoffa C(or)ombo * es, link=no, Cristóbal Colón * pt, Cristóvão Colombo * ca, Cristòfor (or ) * la, Christophorus Columbus. (; born between 25 August and 31 October 1451, died 20 May 1506) was a ...

References

External links

* Iron(II) minerals Manganese(II) minerals Niobium minerals Orthorhombic minerals Minerals in space group 60 Oxide minerals Tantalum minerals {{oxide-mineral-stub

History and etymology

See also

References

External links