Semseyite is a rarely occurring

sulfosalt mineral Sulfosalt minerals are sulfide minerals with the general formula , where *A represents a metal such as copper, lead, silver, iron, and rarely mercury, zinc, vanadium *B usually represents semi-metal such as arsenic, antimony, bismuth, and ra ...

and is part of the class of

lead Lead is a chemical element with the Symbol (chemistry), symbol Pb (from the Latin ) and atomic number 82. It is a heavy metals, heavy metal that is density, denser than most common materials. Lead is Mohs scale of mineral hardness#Intermediate ...

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 ti ...

sulfides 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 ...

. It crystallizes in the

monoclinic In crystallography, the monoclinic crystal system is one of the seven crystal systems. A crystal system is described by three vectors. In the monoclinic system, the crystal is described by vectors of unequal lengths, as in the orthorhombic ...

system with the chemical composition Pb₉Sb₈S₂₁. The mineral forms dark gray to black aggregates.

Etymology and history

Semseyite was first described for an occurrence in the Felsöbánya mine in

Baia Sprie Baia Sprie (; hu, Felsőbánya, german: Mittelstadt) is a town in Maramureș County, northern Romania. Baia Sprie is situated at a distance of from Baia Mare. The town administers three villages: Chiuzbaia (''Kisbánya''), Satu Nou de Sus (''F ...

Romania Romania ( ; ro, România ) is a country located at the crossroads of Central, Eastern, and Southeastern Europe. It borders Bulgaria to the south, Ukraine to the north, Hungary to the west, Serbia to the southwest, Moldova to the east, a ...

in 1881 by József Sándor Krenner (1839–1920). The mineral was named after Hungarian mineralogist

Andor von Semsey Andor may refer to: * ''Andor'' (TV series), a television series in the ''Star Wars'' universe ** Cassian Andor, the titular character * Andor (''Wheel of Time''), a country in Robert Jordan's ''The Wheel of Time'' novels * Andor Technology, ...

(1833–1923).

Occurrence

Semseyite forms in

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 ...

solutions at temperatures between 300 and 350 °C.Andreas Kamrath: “Geology and mineralogy of ore stores Herja”
It occurs in association with bournonite, jamesonite,

sphalerite Sphalerite (sometimes spelled sphaelerite) 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, Mississippi-Va ...

, zinkenite, sorbyite,

guettardite Guettardite is a rare arsenic-antimony lead sulfosalt mineral with the chemical formula . It forms gray black metallic prismatic to acicular crystals with monoclinic symmetry. It is a dimorph of the triclinic twinnite. Discovery and occurrence ...

, jordanite, diaphorite,

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 cry ...

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 giv ...

chalcopyrite Chalcopyrite ( ) is a copper iron sulfide mineral and the most abundant copper ore mineral. It has the chemical formula CuFeS2 and crystallizes in the tetragonal system. It has a brassy to golden yellow color and a hardness of 3.5 to 4 on the Mo ...

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 t ...

arsenopyrite Arsenopyrite (International Mineralogical Association, IMA List of mineral symbols, symbol: Apy) is an iron arsenic sulfide (FeAsS). It is a hard (Mohs scale of mineral hardness, Mohs 5.5-6) metallic, opaque, steel grey to silver white mineral wi ...

and

siderite Siderite is a mineral composed of iron(II) carbonate (FeCO3). It takes its name from the Greek word σίδηρος ''sideros,'' "iron". It is a valuable iron mineral, since it is 48% iron and contains no sulfur or phosphorus. Zinc, magnesium an ...

Images

File:Semseyite-119346.jpg, Semseyite from Baia Sprie, Maramures County, Romania File:Semseyite-168834.jpg, Cluster of semseyite crystals on massive sulfide matrix File:Semseyite-Quartz-168835.jpg, A spray of semseyite crystals perched, freestanding, at the apex of a cluster of quartz crystals File:Semseyite-Sphalerite-199597.jpg, Vug filled with clusters of sprays of lightly iridescent, metallic-lustre semseyite blades on sphalerite matrix

References

{{Commonscat, Semseyite Lead minerals Antimony minerals Sulfide minerals Monoclinic minerals Minerals in space group 15