Hübnerite or hubnerite is a
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 ...
consisting of manganese
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 ...
oxide (chemical formula MnWO
4). It is the manganese
endmember
An endmember (also end-member or end member) in mineralogy is a mineral that is at the extreme end of a mineral series in terms of purity of its chemical composition. Minerals often can be described as solid solutions with varying compositions of ...
of the
manganese
Manganese is a chemical element; it has Symbol (chemistry), symbol Mn and atomic number 25. It is a hard, brittle, silvery metal, often found in minerals in combination with iron. Manganese was first isolated in the 1770s. It is a transition m ...
–iron
wolframite solid solution
A solid solution, a term popularly used for metals, is a homogeneous mixture of two compounds in solid state and having a single crystal structure. Many examples can be found in metallurgy, geology, and solid-state chemistry. The word "solutio ...
series.
It forms reddish brown to black
monoclinic
In crystallography, the monoclinic crystal system is one of the seven crystal systems. A crystal system is described by three Vector (geometric), vectors. In the monoclinic system, the crystal is described by vectors of unequal lengths, as in t ...
prismatic
An optical prism is a transparent optics, optical element with flat, polished surfaces that are designed to refraction, refract light. At least one surface must be angled—elements with two parallel surfaces are ''not'' prisms. The most fami ...
submetallic crystals. The crystals are typically flattened and occur with fine
striations. It has a high
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 ...
of 7.15 and a
Mohs hardness
The Mohs scale ( ) of mineral hardness is a qualitative ordinal scale, from 1 to 10, characterizing scratch resistance of mineral
In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid substance with a fair ...
of 4.5. It is transparent to translucent with perfect cleavage.
Refractive index
In optics, the refractive index (or refraction index) of an optical medium is the ratio of the apparent speed of light in the air or vacuum to the speed in the medium. The refractive index determines how much the path of light is bent, or refrac ...
values are n
α = 2.170 – 2.200, n
β = 2.220, and n
γ = 2.300 – 2.320.
Typical occurrence is in association with high-temperature
hydrothermal
Hydrothermal circulation in its most general sense is the circulation of hot water (Ancient Greek ὕδωρ, ''water'',Liddell, H.G. & Scott, R. (1940). ''A Greek-English Lexicon. revised and augmented throughout by Sir Henry Stuart Jones. with th ...
vein deposits and altered
granite
Granite ( ) is a coarse-grained (phanerite, phaneritic) intrusive rock, intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly coo ...
s with
greisen, granite
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 ...
s and in
alluvial
Alluvium (, ) is loose clay, silt, sand, or gravel that has been deposited by running water in a stream bed, on a floodplain, in an alluvial fan or beach, or in similar settings. Alluvium is also sometimes called alluvial deposit. Alluvium is ...
deposits. It occurs associated with
cassiterite
Cassiterite is a tin oxide mineral, SnO2. It is generally opaque, but it is translucent in thin crystals. Its luster and multiple crystal faces produce a desirable gem. Cassiterite was the chief tin ore throughout ancient history and remains ...
,
arsenopyrite
Arsenopyrite ( IMA symbol: Apy) is an iron arsenic sulfide (FeAsS). It is a hard ( Mohs 5.5–6) metallic, opaque, steel grey to silver white mineral with a relatively high specific gravity of 6.1.
When dissolved in nitric acid, it releases el ...
,
molybdenite
Molybdenite is a mineral of molybdenum disulfide, Mo S2. Similar in appearance and feel to graphite, molybdenite has a lubricating effect that is a consequence of its layered structure. The atomic structure consists of a sheet of molybdenum at ...
,
tourmaline
Tourmaline ( ) is a crystalline silicate mineral, silicate mineral group in which boron is chemical compound, compounded with chemical element, elements such as aluminium, iron, magnesium, sodium, lithium, or potassium. This gemstone comes in a ...
,
topaz
Topaz is a silicate mineral made of aluminium, aluminum and fluorine with the chemical formula aluminium, Alsilicon, Sioxygen, O(fluorine, F, hydroxide, OH). It is used as a gemstone in jewelry and other adornments. Common topaz in its natural ...
,
rhodochrosite
Rhodochrosite is a manganese carbonate mineral with chemical composition Manganese(II) carbonate, MnCO3. In its pure form (rare), it is typically a rose-red colour, but it can also be shades of pink to pale brown. It Streak (mineralogy), streak ...
and
fluorite
Fluorite (also called fluorspar) is the mineral form of calcium fluoride, CaF2. It belongs to the halide minerals. It crystallizes in isometric cubic habit, although octahedral and more complex isometric forms are not uncommon.
The Mohs scal ...
.
It was first described in 1865 for an occurrence in the Erie and Enterprise veins, Mammoth district,
Nye County, Nevada
Nye County is a County (United States), county in the U.S. state of Nevada. As of the 2020 United States census, 2020 census, the population was 51,591. Its county seat is Tonopah, Nevada, Tonopah. At , Nye is Nevada's largest county by area ...
, and named after the German
mining engineer
Mining engineering is the extraction of minerals from the ground. It is associated with many other disciplines, such as mineral processing, exploration, excavation, geology, metallurgy, geotechnical engineering and surveying. A mining engineer m ...
and
metallurgist
Metallurgy is a domain of materials science and engineering that studies the physical and chemical behavior of metallic elements, their inter-metallic compounds, and their mixtures, which are known as alloys.
Metallurgy encompasses both the ...
, Adolf Hübner from
Freiberg
Freiberg () is a university and former mining town in Saxony, Germany, with around 41,000 inhabitants. The city lies in the foreland of the Ore Mountains, in the Saxon urbanization axis, which runs along the northern edge of the Elster and ...
,
Saxony
Saxony, officially the Free State of Saxony, is a landlocked state of Germany, bordering the states of Brandenburg, Saxony-Anhalt, Thuringia, and Bavaria, as well as the countries of Poland and the Czech Republic. Its capital is Dresden, and ...
.
Introduction
Hübnerite is a rare mineral from the rare family wolframite. It is considered to be one of the principle ores of tungsten. It is usually identified by the dark color, one direction of perfect
cleavage
Cleavage may refer to:
Science
* Cleavage (crystal), the way in which a crystal or mineral tends to split
* Cleavage (embryo), the division of cells in an early embryo
* Cleavage (geology), foliation of rock perpendicular to stress, a result of ...
and high specific gravity all serving to distinguish it from other minerals. The first recorded identification of the wolframite family was back in 1948 but it was not added as a mineral until 1951.
Composition
Since hübnerite comes from a family with only two end members it would be easier to explain the composition of the
wolframite family since there is not enough data on hübnerite itself. The primary formula of the wolframite series is . The predominance of either iron or manganese results in formation of one of two minerals, the compositional end-members (
ferberite) and (hübnerite), respectively.
Hübnerite is rarer than ferberite because of the difficulty of substituting manganese for iron. There are also other analogues, such as .
These compounds are usually referred to as "wolframites" because they share the wolframite structure, but are not naturally occurring minerals, typically being produced for industrial applications, e.g., crystal scintillators.
Structure

Hübnerite is a rare end-member of the wolframite group, and has the same crystal structure as other members of the family. The crystal structure contains distorted
tetrahedral
In geometry, a tetrahedron (: tetrahedra or tetrahedrons), also known as a triangular pyramid, is a polyhedron composed of four triangular Face (geometry), faces, six straight Edge (geometry), edges, and four vertex (geometry), vertices. The tet ...
() and
octahedral
In geometry, an octahedron (: octahedra or octahedrons) is any polyhedron with eight faces. One special case is the regular octahedron, a Platonic solid composed of eight equilateral triangles, four of which meet at each vertex. Many types of i ...
() units. The wolframite family represents complete solid solution between Fe
2+ and Mn
2+.
[ In ferberite, the percentage of WO3 is around 76.3% whereas in hübnerite it is around 76.6%. In naturally occurring minerals the percent range falls within 20-80 percent. In the past it was thought that the wolframite structure possesses ]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 ...
symmetry but in fact it possesses monoclinic
In crystallography, the monoclinic crystal system is one of the seven crystal systems. A crystal system is described by three Vector (geometric), vectors. In the monoclinic system, the crystal is described by vectors of unequal lengths, as in t ...
symmetry. Short prismatic, flattened or wedge-shaped crystals are the common morphologies of wolframite crystals. In some rare cases the crystals occur doubly terminated. It is common for the faces to be striated parallel to the c axis.[ In most cases, wolframite is found embedded in ]quartz
Quartz is a hard, crystalline mineral composed of silica (silicon dioxide). The Atom, atoms are linked in a continuous framework of SiO4 silicon–oxygen Tetrahedral molecular geometry, tetrahedra, with each oxygen being shared between two tet ...
as subparallel crystalline masses.
Physical properties
Color differences between members of the wolframite family are clear and marked. The color of hübnerite varies from yellowish brown to reddish brown. Crystal and crystalline masses of hübnerite show a variety of lusters from adamantine, submetallic to resinous luster. In thin splints, hübnerite can be either transparent or translucent. The streak is related to the color being a shade lighter.[ All the wolframite minerals exhibit perfect cleavage on . On and , parting is less well-developed. Hübnerite exhibits brittle and uneven fracture. It is common for all members of the wolframite family to show simple contact twins on or rarely interpenetrant twins on . The hardness of hübnerite is between 4 and 4.5 and its specific gravity is between 7.12 and 7.18.
]
Geological occurrence
Hübnerite is a rare member of the wolframite group. Hübnerite is usually found within pegmatites and high-temperature quartz veins. Hübnerite does not occur on its own, but is typically associated with other minerals such as cassiterite
Cassiterite is a tin oxide mineral, SnO2. It is generally opaque, but it is translucent in thin crystals. Its luster and multiple crystal faces produce a desirable gem. Cassiterite was the chief tin ore throughout ancient history and remains ...
, scheelite
Scheelite is a calcium tungstate mineral with the chemical formula Ca W O4. It is an important ore of tungsten (wolfram). Scheelite is originally named after Swedish chemist Carl Wilhelm Scheele (1742–1786). Well-formed crystals are sought ...
, quartz
Quartz is a hard, crystalline mineral composed of silica (silicon dioxide). The Atom, atoms are linked in a continuous framework of SiO4 silicon–oxygen Tetrahedral molecular geometry, tetrahedra, with each oxygen being shared between two tet ...
, galena
Galena, also called lead glance, is the natural mineral form of lead(II) sulfide (PbS). It is the most important ore of lead and an important source of silver.
Galena is one of the most abundant and widely distributed sulfide minerals. It crysta ...
, arsenopyrite
Arsenopyrite ( IMA symbol: Apy) is an iron arsenic sulfide (FeAsS). It is a hard ( Mohs 5.5–6) metallic, opaque, steel grey to silver white mineral with a relatively high specific gravity of 6.1.
When dissolved in nitric acid, it releases el ...
, native bismuth
Bismuth is a chemical element; it has symbol Bi and atomic number 83. It is a post-transition metal and one of the pnictogens, with chemical properties resembling its lighter group 15 siblings arsenic and antimony. Elemental bismuth occurs nat ...
, pyrite
The mineral pyrite ( ), or iron pyrite, also known as fool's gold, is an iron sulfide with the chemical formula Fe S2 (iron (II) disulfide). Pyrite is the most abundant sulfide mineral.
Pyrite's metallic luster and pale brass-yellow hue ...
, and sphalerite
Sphalerite is a sulfide mineral with the chemical formula . It is the most important ore of zinc. Sphalerite is found in a variety of deposit types, but it is primarily in Sedimentary exhalative deposits, sedimentary exhalative, Carbonate-hoste ...
.
History and uses
Hübnerite was not the original name giving to the mineral. Hübnerite is a synonym of the original name, megabasite. The name megabasite was given to the mineral by A. Breithaupt in 1852. The name hübnerite was given to the mineral by E.N. Riotte in 1865 to honor the metallurgist Adolph Hübner.[
Hübnerite is primarily used as a source of tungsten. Tungsten is used to harden metal in the manufacture of high-speed tools.][
]
See also
*List of minerals
This is a list of minerals which have Wikipedia articles.
Minerals are distinguished by various chemical and physical properties. Differences in chemical composition and crystal structure distinguish the various ''species''. Within a mineral speci ...
*List of minerals named after people
This is a list of minerals named after people. The chemical composition of the mineral follows the name.
A
* Abelsonite: – American physicist Philip Hauge Abelson (1913–2004)
* Abswurmbachite: – German mineralogist Irmgard Abs-Wurmbac ...
References
*
{{DEFAULTSORT:Hubnerite
Manganese(II) minerals
Tungstate minerals
Monoclinic minerals
Minerals in space group 14
Minerals described in 1865