Béhierite is a very rare mineral,
a natural
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 is ...
borate
A borate is any of several boron oxyanions, negative ions consisting of boron and oxygen, such as orthoborate , metaborate , or tetraborate ; or any salt with such anions, such as sodium metaborate, and disodium tetraborate . The name also refe ...
of the formula (Ta,Nb)BO
4.
Béhierite is also one of the most simple tantalum minerals. It contains simple
tetrahedral
In geometry, a tetrahedron (plural: tetrahedra or tetrahedrons), also known as a triangular pyramid, is a polyhedron composed of four triangular faces, six straight edges, and four vertex corners. The tetrahedron is the simplest of all the o ...
borate
anions
An ion () is an atom or molecule with a net electrical charge.
The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by convent ...
, instead of more common among minerals, planar BO
3 groups. It forms a solid solution with its
niobium
Niobium is a chemical element with chemical symbol Nb (formerly columbium, Cb) and atomic number 41. It is a light grey, crystalline, and ductile transition metal. Pure niobium has a Mohs hardness rating similar to pure titanium, and it has sim ...
-analogue,
schiavinatoite
Schiavinatoite is a very rare mineral, a natural niobium borate with the chemical formula .Demartin, F., Diella, V., Gramaccioli, C.M., and Pezzotta, F., 2001. Schiavinatoite, , the Nb analogue of behierite. European Journal of Mineralogy 13, 159- ...
. Both have zircon-type structure (tetragonal, space group ''I''4
1/''amd'') and are found in
pegmatites
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 comp ...
.
Béhierite and holtite are minerals with essential
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 is ...
and
boron
Boron is a chemical element with the symbol B and atomic number 5. In its crystalline form it is a brittle, dark, lustrous metalloid; in its amorphous form it is a brown powder. As the lightest element of the ''boron group'' it has th ...
.
Béhierite was named for
Jean Béhier (1903–1965), who discovered the mineral in 1959, as a French mineralogist, active in the Service Géologique, on the island of
Madagascar
Madagascar (; mg, Madagasikara, ), officially the Republic of Madagascar ( mg, Repoblikan'i Madagasikara, links=no, ; french: République de Madagascar), is an island country in the Indian Ocean, approximately off the coast of East Africa ...
.
[
]
Occurrence and association
Béhierite occurs in granitic pegmatites in Manjaka and Antsongombato, Madagascar. Associated minerals are albite
Albite is a plagioclase feldspar mineral. It is the sodium endmember of the plagioclase solid solution series. It represents a plagioclase with less than 10% anorthite content. The pure albite endmember has the formula . It is a tectosilicate. I ...
, manganese
Manganese is a chemical element with the symbol Mn and atomic number 25. It is a hard, brittle, silvery metal, often found in minerals in combination with iron. Manganese is a transition metal with a multifaceted array of industrial alloy use ...
-bearing apatite
Apatite is a group of phosphate minerals, usually hydroxyapatite, fluorapatite and chlorapatite, with high concentrations of OH−, F− and Cl− ions, respectively, in the crystal. The formula of the admixture of the three most common e ...
-group mineral, lepidolite
Lepidolite is a lilac-gray or rose-colored member of the mica group of minerals with chemical formula . It is the most abundant lithium-bearing mineral and is a secondary source of this metal. It is the major source of the alkali metal rubidium.
...
, elbaite
Elbaite, a sodium, lithium, aluminium boro-silicate, with the chemical composition Na(Li1.5Al1.5)Al6Si6O18(BO3)3(OH)4, is a mineral species belonging to the six-member ring cyclosilicate tourmaline group.
Elbaite forms three series, with dravite, ...
or elbaite–liddicoatite
Fluor-liddicoatite is a rare member of the tourmaline group of minerals, elbaite subgroup, and the theoretical calcium endmember of the elbaite-fluor-liddicoatite series; the pure end-member has not yet been found in nature. Fluor-liddicoatite is ...
, feldspar
Feldspars are a group of rock-forming aluminium tectosilicate minerals, also containing other cations such as sodium, calcium, potassium, or barium. The most common members of the feldspar group are the ''plagioclase'' (sodium-calcium) feldsp ...
, pollucite
Pollucite is a zeolite mineral with the formula with iron, calcium, rubidium and potassium as common substituting elements. It is important as a significant ore of caesium and sometimes rubidium. It forms a solid solution series with analcime. I ...
, quartz
Quartz is a hard, crystalline mineral composed of silica (silicon dioxide). The atoms are linked in a continuous framework of SiO4 silicon-oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical form ...
, rhodizite
The borate minerals are minerals which contain a borate anion group. The borate (BO3) units may be polymerised similar to the SiO4 unit of the silicate mineral class. This results in B2O5, B3O6, B2O4 anions as well as more complex structures whic ...
, and schiavinatoite
Schiavinatoite is a very rare mineral, a natural niobium borate with the chemical formula .Demartin, F., Diella, V., Gramaccioli, C.M., and Pezzotta, F., 2001. Schiavinatoite, , the Nb analogue of behierite. European Journal of Mineralogy 13, 159- ...
.
Crystal structure
Crystal structure of synthetic TaBO4 was refined by Range et al. (1996). As béhierite is analogous to schiavinatoite
Schiavinatoite is a very rare mineral, a natural niobium borate with the chemical formula .Demartin, F., Diella, V., Gramaccioli, C.M., and Pezzotta, F., 2001. Schiavinatoite, , the Nb analogue of behierite. European Journal of Mineralogy 13, 159- ...
, their crystal structures are expected to be similar.[Demartin, F., Diella, V., Gramaccioli, C.M., and Pezzotta, F., 2001. Schiavinatoite, (Nb,Ta)BO4, the Nb analogue of behierite. European Journal of Mineralogy 13, 159-165]
References
{{DEFAULTSORT:Behierite
Borate minerals
Tantalum minerals
Tetragonal minerals
Minerals in space group 141
Minerals described in 1959