Ullmannite is a

nickel Nickel is a chemical element with symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel is a hard and ductile transition metal. Pure nickel is chemically reactive but large pieces are slow to ...

antimony Antimony is a chemical element with the symbol Sb (from la, stibium) and atomic number 51. A lustrous gray metalloid, it is found in nature mainly as the sulfide mineral stibnite (Sb2S3). Antimony compounds have been known since ancient time ...

sulfide Sulfide (British English also sulphide) is an inorganic anion of sulfur with the chemical formula S2− or a compound containing one or more S2− ions. Solutions of sulfide salts are corrosive. ''Sulfide'' also refers to chemical compounds lar ...

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

with formula: NiSbS. Considerable substitution occurs with

cobalt Cobalt is a chemical element with the symbol Co and atomic number 27. As with nickel, cobalt is found in the Earth's crust only in a chemically combined form, save for small deposits found in alloys of natural meteoric iron. The free element, pr ...

and

iron Iron () is a chemical element with symbol Fe (from la, ferrum) 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, right in f ...

in the nickel site along with bismuth and

arsenic Arsenic is a chemical element with the symbol As and atomic number 33. Arsenic occurs in many minerals, usually in combination with sulfur and metals, but also as a pure elemental crystal. Arsenic is a metalloid. It has various allotropes, but ...

in the antimony site. A solid solution series exists with the high cobalt willyamite.

Physical properties

Ullmannite is steel-gray to tin white in color with a metallic luster, has a

Mohs hardness The Mohs scale of mineral hardness () is a qualitative ordinal scale, from 1 to 10, characterizing scratch resistance of various minerals through the ability of harder material to scratch softer material. The scale was introduced in 1812 by th ...

of 5 to 5.5 and a

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 (molecule), wa ...

of 6.65. Initially thought to be of two species, tetrahedral and cubic, it was later confirmed that both samples conformed to the 23 point group of the isometric crystal class and typically exhibits cubic, octahedral, or pyritohedral forms although euhedral crystals are rare. Variance in its chemical composition has been shown to be responsible for loss of symmetry and variations in striation patterns. Ullmannite crystals are usually less than 2 mm, however larger have been identified in especially antimony rich environments. Ullmannite commonly displays interpenetration twins as well as enantiomorphic twinning along 10

Occurrence

It is a member of the

cobaltite Cobaltite is a sulfide mineral composed of cobalt, arsenic, and sulfur, Co As S. Its impurities may contain up to 10% iron and variable amounts of nickel.Klein, Cornelus and Cornrlius Hurlbut, 1996, ''Manual of Mineralogy'', 20th ed., Wiley, p.2 ...

group and forms a series with willyamite (). It occurs with nickeline, gersdorffite, pentlandite, chalcopyrite, pyrrhotite,

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 cryst ...

tetrahedrite Tetrahedrite is a copper antimony sulfosalt mineral with formula: . It is the antimony endmember of the continuous solid solution series with arsenic-bearing tennantite. Pure endmembers of the series are seldom if ever seen in nature. Of the two, ...

and

dyscrasite The silver antimonide mineral dyscrasite has the chemical formula Ag3Sb. It is an opaque, silver white, metallic mineral which crystallizes in the orthorhombic crystal system. It forms pyramidal crystals up to and can also form cylindrical and ...

in hydrothermal deposits. Principal localities are in

Germany Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated betwe ...

, it is also found in

Austria Austria, , bar, Östareich officially the Republic of Austria, is a country in the southern part of Central Europe, lying in the Eastern Alps. It is a federation of nine states, one of which is the capital, Vienna, the most populous ...

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

France France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of Overseas France, overseas regions and territories in the Americas and the Atlantic Ocean, Atlantic, Pacific Ocean, Pac ...

England England is a country that is part of the United Kingdom. It shares land borders with Wales to its west and Scotland to its north. The Irish Sea lies northwest and the Celtic Sea to the southwest. It is separated from continental Europe b ...

, and

Wales Wales ( cy, Cymru ) is a Countries of the United Kingdom, country that is part of the United Kingdom. It is bordered by England to the Wales–England border, east, the Irish Sea to the north and west, the Celtic Sea to the south west and the ...

. It was first described in 1843 for an occurrence in the Storch und Schöneberg Mine,

North Rhine-Westphalia North Rhine-Westphalia (german: Nordrhein-Westfalen, ; li, Noordrien-Wesfale ; nds, Noordrhien-Westfalen; ksh, Noodrhing-Wäßßfaale), commonly shortened to NRW (), is a States of Germany, state (''Land'') in Western Germany. With more tha ...

. Specimens of ullmannite were found at

Sarrabus Sarrabus-Gerrei is a sub-region of south-eastern Sardinia, Italy. Sarrabus Traditionally Sarrabus, probably from the Roman-time city of Sarcopos, occupies the area of the communes of Castiadas, Muravera, San Vito and Villaputzu, corresponding to ...

Sardinia Sardinia ( ; it, Sardegna, label=Italian, Corsican and Tabarchino ; sc, Sardigna , sdc, Sardhigna; french: Sardaigne; sdn, Saldigna; ca, Sardenya, label=Algherese and Catalan) is the second-largest island in the Mediterranean Sea, after ...

, Italy in 1887. The crystals of the specimens from Sarrabus were described as hemihedral with parallel faces, whereas specimens from Lölling in present-day Austria were hemihedral with inclined faces.

Origin of name

Ullmannite was named for

German German(s) may refer to: * Germany (of or related to) **Germania (historical use) * Germans, citizens of Germany, people of German ancestry, or native speakers of the German language ** For citizens of Germany, see also German nationality law **Ger ...

chemist A chemist (from Greek ''chēm(ía)'' alchemy; replacing ''chymist'' from Medieval Latin ''alchemist'') is a scientist trained in the study of chemistry. Chemists study the composition of matter and its properties. Chemists carefully describe th ...

and mineralogist, Johann Christoph Ullmann (1771–1821), one of the fathers of systematic mineralogy. Ullmann established a mineral collection (now the basis for the internationally renowned Museum of Mineralogy in Marbur

and authored ''Ein Systematisch-Tabellarische Übersicht der Mineralogisch einfachen Fossilien'', one of the first attempts to provide a structured organization to the observed minerals of the day.

References

* Palache, C., H. Berman, and C. Frondel (1944) ''Dana’s system of mineralogy'', (7th edition), v. I, 301–302. {{Commons category, Ullmannite Nickel minerals Antimonide minerals Sulfide minerals Cubic minerals Minerals in space group 198 Minerals described in 1843

Physical properties

Occurrence

Origin of name

See also

References