Columbite, also called niobite, niobite-tantalite and columbate, with a general chemical formula of , is a black

mineral In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid substance with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. (2011): Mi ...

group that is an ore of niobium. It has a submetallic luster, a high density, and is a niobate of iron and manganese. Niobite has many applications in aerospace, construction and the medical industry. Dating columbite minerals is primarily completed by uranium lead (U-Pb) dating, a slow process. Columbite has the same composition and crystal symmetry (

orthorhombic In crystallography, the orthorhombic crystal system is one of the 7 crystal systems. Orthorhombic Lattice (group), lattices result from stretching a cubic crystal system, cubic lattice along two of its orthogonal pairs by two different factors, res ...

) as tantalite. In fact, the two are often grouped together as a semi-singular mineral series called columbite-tantalite or coltan in many mineral guides. However, tantalite has a much greater

specific gravity Relative density, also called specific gravity, is a dimensionless quantity defined as the ratio of the density (mass of a unit volume) of a substance to the density of a given reference material. Specific gravity for solids and liquids is nea ...

than columbite, more than 8.0 compared to columbite's 5.2. The formation of columbite depends on the concentrations of metals present that affect the crystalline structure of the mineral and the environmental impact. Columbite is a polymorph of tapiolite; they have the 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 (geometry), cube becomes a rectangular Pri ...

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

thorium Thorium is a chemical element; it has symbol Th and atomic number 90. Thorium is a weakly radioactive light silver metal which tarnishes olive grey when it is exposed to air, forming thorium dioxide; it is moderately soft, malleable, and ha ...

and

uranium Uranium is a chemical element; it has chemical symbol, 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. Ura ...

, making it radioactive. Coltan, a tantalum dominate species of columbite, is often mined by

artisan An artisan (from , ) is a skilled craft worker who makes or creates material objects partly or entirely by hand. These objects may be functional or strictly decorative, for example furniture, decorative art, sculpture, clothing, food ite ...

and small scale miners with risks to the environment and human health due to unregulated working conditions.

History and etymology

This mineral group was first found in

Haddam, Connecticut Haddam is a town in Middlesex County, Connecticut, United States. The town is part of the Lower Connecticut River Valley Planning Region. The population was 8,452 at the time of the 2020 census. It is the only town in Connecticut that the Conne ...

, in the United States. The occurrence of columbite in the United States was made known on April 13, 1905, through the publication of research into the composition of an older specimen, presumably stemming from

John Winthrop John Winthrop (January 12, 1588 – March 26, 1649) was an English Puritan lawyer and a leading figure in the founding of the Massachusetts Bay Colony, the second major settlement in New England following Plymouth Colony. Winthrop led the fir ...

(1606–1676), first Governor of the

Connecticut Colony The Connecticut Colony, originally known as the Connecticut River Colony, was an English colony in New England which later became the state of Connecticut. It was organized on March 3, 1636, as a settlement for a Puritans, Puritan congregation o ...

and avid mineral collector. Amidst 600 other samples, the relevant specimen had been donated by the Governor's 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. He had a collection of 71,000 items which he bequeathed to the British nation, thus providing the foundation of the British ...

, 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 Winthrop's becoming a

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

in 1737. In 1801,

Charles Hatchett Charles Hatchett Fellow of the Royal Society, 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 ...

had discovered the element

niobium Niobium is a chemical element; it has chemical symbol, symbol Nb (formerly columbium, Cb) and atomic number 41. It is a light grey, crystalline, and Ductility, ductile transition metal. Pure niobium has a Mohs scale of mineral hardness, Mohs h ...

in the same specimen, which he had named columbium in honour of explorer

Christopher Columbus Christopher Columbus (; between 25 August and 31 October 1451 – 20 May 1506) was an Italians, Italian explorer and navigator from the Republic of Genoa who completed Voyages of Christopher Columbus, four Spanish-based voyages across the At ...

Columbite species

Columbite forms opaque crystals that are black to dark brown in colour. The formation of the crystals vary based on the species present. Columbite forms a series with the

tantalum Tantalum is a chemical element; it has Symbol (chemistry), symbol Ta and atomic number 73. It is named after Tantalus, a figure in Greek mythology. Tantalum is a very hard, ductility, ductile, lustre (mineralogy), lustrous, blue-gray transition ...

-dominant analogue ferrotantalite and the manganese-dominant analogue manganocolumbite. Manganocolumbite has a chemical formula of (Mn, Fe)(Nb, Ta)₂O₆, often with small concentrations of tantalum and iron. Manganocolumbite is often found in pegmatites, course-grained igneous rocks. Ferrocolumbite-pb50a

The iron-rich member of the columbite group is ferrocolumbite, FeNb₂O₆, and small concentrations of

tin Tin is a chemical element; it has symbol Sn () and atomic number 50. A silvery-colored metal, tin is soft enough to be cut with little force, and a bar of tin can be bent by hand with little effort. When bent, a bar of tin makes a sound, the ...

and

tungsten Tungsten (also called wolfram) is a chemical element; it has symbol W and atomic number 74. It is a metal found naturally on Earth almost exclusively in compounds with other elements. It was identified as a distinct element in 1781 and first ...

may be present. This species of columbite is often found in pegmatites as course-grained igneous rocks. Yttrocolumbite is the

yttrium Yttrium is a chemical element; it has Symbol (chemistry), symbol Y and atomic number 39. It is a silvery-metallic transition metal chemically similar to the lanthanides and has often been classified as a "rare-earth element". Yttrium is almost a ...

-rich columbite with the formula , is a

radioactive Radioactive decay (also known as nuclear decay, radioactivity, radioactive disintegration, or nuclear disintegration) is the process by which an unstable atomic nucleus loses energy by radiation. A material containing unstable nuclei is conside ...

mineral found in

Mozambique Mozambique, officially the Republic of Mozambique, is a country located in Southeast Africa bordered by the Indian Ocean to the east, Tanzania to the north, Malawi and Zambia to the northwest, Zimbabwe to the west, and Eswatini and South Afr ...

. This mineral forms due to pegmatites and rare-metal granites.

Structure

Columbite atoms form an octahedral structure where

atoms surround an oxygen atom. Overall, Columbite forms

crystals which give approximate lengths of the crystal axes as a ≈ 14.27, b ≈ 5.73, and c ≈ 5.06 Å. Different columbite species such as manganocolumbite or ferrocolumbite can change the lengths of the crystal axes. Face-centered orthorhombic

Since columbite can form species with other minerals, the physical properties of the mineral can change. When ferrocolumbite is introduced to heat, an equal expansion of the ‘a’ and ‘b’ axis occurs. In addition, due to the size of the ions and the overall structure, ferrocolumbite is more compressible than manganocolumbite. When manganocolumbite is introduced to heat, an expansion of the ‘a’ axis occurs resulting in an uneven change to the structure.

Applications

When niobite is extracted from columbite, in the ore refining process, applications can be observed in the aerospace, construction, and medical industry. In the aerospace industry, super alloys can be created. Super alloys from niobite create a low mass, and high resistance material often used in spacecrafts. In construction, some high-strength low-alloy (HSLA) steel is created from niobite. In addition, niobite extracted from columbite can be used to create electronic components used in medical equipment such as

magnetic resonance imaging Magnetic resonance imaging (MRI) is a medical imaging technique used in radiology to generate pictures of the anatomy and the physiological processes inside the body. MRI scanners use strong magnetic fields, magnetic field gradients, and ...

(MRI) and

nuclear magnetic resonance Nuclear magnetic resonance (NMR) is a physical phenomenon in which nuclei in a strong constant magnetic field are disturbed by a weak oscillating magnetic field (in the near field) and respond by producing an electromagnetic signal with a ...

(NMR).

Formation

Columbite is often found in

pegmatite A pegmatite is an igneous rock showing a very coarse texture, with large interlocking crystals usually greater in size than and sometimes greater than . Most pegmatites are composed of quartz, feldspar, and mica, having a similar silicic c ...

and alluvial deposits, as well as

granitic A granitoid is a broad term referring to a diverse group of coarse-grained igneous rocks that are widely distributed across the globe, covering a significant portion of the Earth's exposed surface and constituting a large part of the continental ...

rocks. Columbite minerals are mainly composed of

magnesium Magnesium is a chemical element; it has Symbol (chemistry), symbol Mg and atomic number 12. It is a shiny gray metal having a low density, low melting point and high chemical reactivity. Like the other alkaline earth metals (group 2 ...

iron Iron is a chemical element; it has symbol Fe () and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, forming much of Earth's o ...

, and

where trace amounts of

titanium Titanium is a chemical element; it has symbol Ti and atomic number 22. Found in nature only as an oxide, it can be reduced to produce a lustrous transition metal with a silver color, low density, and high strength, resistant to corrosion in ...

, and

scandium Scandium is a chemical element; it has Symbol (chemistry), symbol Sc and atomic number 21. It is a silvery-white metallic d-block, d-block element. Historically, it has been classified as a rare-earth element, together with yttrium and the lantha ...

have been observed. The overall composition of columbite influences the crystalline structure resulting in different formation processes. Currently, there are two prominent theories for the formation of columbite. One theory was developed due to a strong attraction of

and

, within columbite, to silicate melts found in the earth's crust or mantle. In addition, the presence of magma forms columbite by undergoing two

crystallization Crystallization is a process that leads to solids with highly organized Atom, atoms or Molecule, molecules, i.e. a crystal. The ordered nature of a crystalline solid can be contrasted with amorphous solids in which atoms or molecules lack regu ...

processes. The first

process creates a

core and the second

process creates a

rim. This theory is prominent due to the texture of the mineral during the fluid stage, and the magmatic fractional

that occurs during formation. Another prominent theory of the formation of

and

, in Columbite minerals, occurs due to hydrothermal fluids. This theory suggests that hydrothermal fluids interact with columbite during formation and as a result irregular crystals are formed. It is possible that both theories work in conjunction with one another to form columbite minerals as well as different species of columbite such as mangancolumbite, ferrocolumbite, and yttrocolumbite.

Environmental impact

Columbite minerals have the potential to be radioactive due to trace amounts of

and

. Radioactive minerals are unstable due to the emission of

radiation In physics, radiation is the emission or transmission of energy in the form of waves or particles through space or a material medium. This includes: * ''electromagnetic radiation'' consisting of photons, such as radio waves, microwaves, infr ...

which causes negative impacts to the environment and human health. Each country has different laws regarding the transportation of radioactive material. When mining columbite, contamination of ground and surface water are a concern due to the presence of

heavy metals upright=1.2, Crystals of lead.html" ;"title="osmium, a heavy metal nearly twice as dense as lead">osmium, a heavy metal nearly twice as dense as lead Heavy metals is a controversial and ambiguous term for metallic elements with relatively h ...

in waste rock. In addition, waste rock can lead to

acid mine drainage Acid mine drainage, acid and metalliferous drainage (AMD), or acid rock drainage (ARD) is the outflow of acidic water from metal mines and coal mines. Acid rock drainage occurs naturally within some environments as part of the rock weatherin ...

which can affect ground and surface water. To obtain pure columbite, a large quantity of waste rock is produced, leading to negative impacts to the surrounding environment. During the extraction of niobite or tantalum from columbite, strong acids at high temperatures are used that have negative impacts to the environment.

Hydrofluoric acid Hydrofluoric acid is a solution of hydrogen fluoride (HF) in water. Solutions of HF are colorless, acidic and highly corrosive. A common concentration is 49% (48–52%) but there are also stronger solutions (e.g. 70%) and pure HF has a boiling p ...

and

sulfuric acid Sulfuric acid (American spelling and the preferred IUPAC name) or sulphuric acid (English in the Commonwealth of Nations, Commonwealth spelling), known in antiquity as oil of vitriol, is a mineral acid composed of the elements sulfur, oxygen, ...

are used in the ore refining processes between temperatures of 250-300^oC. These acids can cause

soil acidification Soil acidification is the buildup of hydrogen cations, which reduces the soil pH. Chemically, this happens when a proton donor gets added to the soil. The donor can be an acid, such as nitric acid, sulfuric acid, or carbonic acid. It can also be a ...

air pollution Air pollution is the presence of substances in the Atmosphere of Earth, air that are harmful to humans, other living beings or the environment. Pollutants can be Gas, gases like Ground-level ozone, ozone or nitrogen oxides or small particles li ...

, and

water pollution Water pollution (or aquatic pollution) is the contamination of Body of water, water bodies, with a negative impact on their uses. It is usually a result of human activities. Water bodies include lakes, rivers, oceans, aquifers, reservoirs and ...

that, in turn, affects ecosystems. Current technology, in the ore refining of columbite, is not selective which leads to impurities present in refined Columbite samples. To remove impurities, a greater concentration of acid is required, leading to a greater potential of environmental hazards.

Dating

There are three applications to dating columbite group minerals each with advantages and disadvantages. These methods are uranium lead (U-Pb) dating, laser ablation

inductively coupled plasma mass spectrometry Inductively coupled plasma mass spectrometry (ICP-MS) is a type of mass spectrometry that uses an inductively coupled plasma to ionize the sample. It atomizes the sample and creates atomic and small polyatomic ions, which are then detected. It i ...

(LA-ICP-MS), and

secondary ion mass spectrometry Secondary-ion mass spectrometry (SIMS) is a technique used to analyze the composition of solid surfaces and thin films by sputtering the surface of the specimen with a focused primary ion beam and collecting and analyzing ejected secondary ions ...

(SIMS). The U-Pb method, can determine the location, and age of a columbite mineral group by the U/Pb ratio. This method is often paired with isotope dilution-thermal ionization mass spectrometry (ID-TIMS) to increase precision. The LA-ICP-MS method is used in situ to date columbite-tantalite minerals with less than five percent error on the isotopic ratio of uranium and lead. The SIMS method has a high spatial resolution and has a high accuracy in measuring lead isotopes in columbite minerals. The LA-ICP-MS and SIMS method are not commonly used due to the lack of certified reference material.

Artisanal and small scale mining

Artisanal An artisan (from , ) is a skilled craft worker who makes or creates material objects partly or entirely by hand. These objects may be functional or strictly decorative, for example furniture, decorative art, sculpture, clothing, food ite ...

and small-scale mining provides jobs for millions of people but typically has negative impacts to human health and the environment. This type of mining is executed by small groups of people, typically under a larger mining cooperation, with simple extraction equipment. This simple extraction equipment can include pickaxes,

shovels A shovel is a tool used for digging, lifting, and moving bulk materials, such as soil, coal, gravel, snow, sand, or ore. Most shovels are hand tools consisting of a broad blade fixed to a medium-length handle. Shovel blades are usually made of ...

, basins, and minimal heavy machinery.

Coltan 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 A ...

, the tantalum dominant species of columbite, is often mined artisanally due to its vast applications in electronics.

and small-scale mining of materials are common in regions such as Africa, Asia, Oceania, Central American, and South America. While this type of mining is important for local economies and livelihood, it is often unregulated, which leads to

illegal mining Illegal mining is mining activity that is undertaken without state permission. Illegal mining is the extraction of precious metals/rocks without following the proper procedures to participate in legal mining activity. These procedures include pe ...

and unsafe working conditions. Due to unregulated conditions, the mistreatment of artisanal miners, violence, illegal trading, and sometimes

child labour Child labour is the exploitation of children through any form of work that interferes with their ability to attend regular school, or is mentally, physically, socially and morally harmful. Such exploitation is prohibited by legislation w ...

can occur. In addition, long term health effects are common when mining coltan, due to the presence of radioactive material within the mineral. In countries such as Sierra Leone, Liberia, and the Democratic Republic of the Congo, lucrative trading of minerals, such as coltan, has occurred due to lack of state control of

artisanal An artisan (from , ) is a skilled craft worker who makes or creates material objects partly or entirely by hand. These objects may be functional or strictly decorative, for example furniture, decorative art, sculpture, clothing, food ite ...

and small-scale mining in the region.

References

External links

* {{Authority control Iron(II) minerals Manganese(II) minerals Niobium minerals Orthorhombic minerals Minerals in space group 60 Oxide minerals Tantalum minerals

History and etymology

Columbite species

Structure

Applications

Formation

Environmental impact

Dating

Artisanal and small scale mining

Further reading

See also

References

External links