Franckeite, chemical formula Pb
5Sn
3Sb
2S
14, belongs to a family of complex
sulfide mineral
The sulfide minerals are a class of minerals containing sulfide (S2−) or disulfide (S22−) as the major anion. Some sulfide minerals are economically important as metal ores. The sulfide class also includes the selenides, the tellurides, the ...
s. Franckeite is a
sulfosalt
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 rarely ...
. It is closely related to
cylindrite
Cylindrite is a sulfosalt mineral containing tin, lead, antimony and iron with formula: Pb3 Sn4 Fe Sb2 S14. It forms triclinic pinacoidal crystals which often occur as tubes or cylinders which are in fact rolled sheets. It has a black to lead g ...
.
It was first described in 1893 for an occurrence in Chocaya,
Potosí Department
Potosí (; Aymara language, Aymara: ''Putusi''; qu, P'utuqsi) is a Departments of Bolivia, department in southwestern Bolivia. It comprises 118,218 km2 with 823,517 inhabitants (2012 census). The capital is the city of Potosí.
It is most ...
,
Bolivia
, image_flag = Bandera de Bolivia (Estado).svg
, flag_alt = Horizontal tricolor (red, yellow, and green from top to bottom) with the coat of arms of Bolivia in the center
, flag_alt2 = 7 × 7 square p ...
. It is named after the mining engineers, Carl and Ernest Francke.
[ It can be found in Bolivia at Poopó in Oruro and at Las Aminas, southeast of Chocaya, in Potosi. Franckeite has an average density of 5.7 and can be both grayish black, blackish gray in color.
It occurs 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 ...
silver-tin deposits in Bolivia and in contact metamorphosed limestone
Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms whe ...
deposit in the Kalkar quarry in California
California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...
. It occurs with cylindrite, teallite
Teallite is a sulfide mineral of tin and lead with chemical formula: Pb Sn S2. It occurs in hydrothermal veins and is sometimes mined as an ore of tin. Teallite forms soft silvery grey mica-like plates and crystallizes in the orthorhombic syste ...
, plagionite, zinkenite
Zinkenite is a steel-gray metallic sulfosalt mineral composed of lead antimony sulfide Pb9 Sb22 S42. Zinkenite occurs as acicular needle-like crystals.
It was first described in 1826 for an occurrence in the Harz Mountains, Saxony-Anhalt, Germa ...
, 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 t ...
, wurtzite
Wurtzite is a zinc and iron sulfide mineral with the chemical formula , a less frequently encountered Polymorphism (materials science), structural polymorph form of sphalerite. The iron content is variable up to eight percent.Palache, Charles, Har ...
, pyrrhotite
Pyrrhotite is an iron sulfide mineral with the formula Fe(1-x)S (x = 0 to 0.2). It is a nonstoichiometric variant of FeS, the mineral known as troilite.
Pyrrhotite is also called magnetic pyrite, because the color is similar to pyrite and it is ...
,
marcasite
The mineral marcasite, sometimes called “white iron pyrite”, is iron sulfide (FeS2) with orthorhombic crystal structure. It is physically and crystallographically distinct from pyrite, which is iron sulfide with cubic crystal structure. Both ...
, 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 eleme ...
, 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 ...
, pyrite
The mineral pyrite (), or iron pyrite, also known as fool's gold, is an iron sulfide with the chemical formula Iron, FeSulfur, S2 (iron (II) disulfide). Pyrite is the most abundant sulfide mineral.
Pyrite's metallic Luster (mineralogy), lust ...
, 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 deposits, sedimen ...
, 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 and ...
and stannite.[
]
See also
*List of minerals
This is a list of minerals for which there are articles on Wikipedia.
Minerals are distinguished by various chemical and physical properties. Differences in chemical composition and crystal structure distinguish the various ''species''. Within a m ...
*List of minerals named after people
This is a list of minerals named after people. The chemical composition follows name.
A
*Abelsonite: C31H32N4Ni – American physicist Philip Hauge Abelson (1913–2004)alfred
*Abswurmbachite: Cu2+Mn3+6O8SiO4 – German mineralogist I ...
References
Lead minerals
Tin minerals
Antimony minerals
Sulfosalt minerals
Triclinic minerals
Minerals in space group 2
{{sulfide-mineral-stub