cassiterite


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cassiterite

(kəsĭt`ərīt), heavy, brown-to-black mineral, tin oxide, SnO2, crystallizing in the tetragonal system. It is found as short prismatic crystals and as irregular masses, usually in veins and replacement deposits associated with granites. Since it is hard, heavy, and resistant to weathering, it often concentrates in alluvial deposits derived from cassiterite-bearing rocks. It is the principal ore of tin and is mined in many countries; the most important sources are Malaysia, Thailand, China, Indonesia, Bolivia, and Russia. Except for Bolivia, nearly all of this production is from alluvial deposits.

Cassiterite

 

(or tinstone), a mineral with the chemical composition Sno2. Theoretically it contains 78.62 percent Sn but usually includes impurities of Nb, Ta, Zr, Sc, W, and Fe; thus, the Sn content varies within 68–78 percent.

Cassiterite crystallizes in the tetragonal system, forming prismatic or dipyrimidal crystals. Geniculated twins are characteristic. The crystalline structure is analogous to that of rutile. Cassiterite is usually encountered in the form of small and large crystals, drusoid aggregates, or compact granular masses as well as in the form of cryptocrystalline, colloform segregations, concretions, and sinter formations. The color is dark brown, almost black, yellow with a reddish brown cast; nearly colorless varieties are also known. Cassiterite has an adamantine luster, a hardness of 6–7 on the mineralogical scale, and a density of 6, 040–7, 120 kg/m3 (lowest in light-colored cassiterite).

The deposits are usually genetically linked with granitic rocks. The most interesting commercial accumulations of the mineral are characteristic for hydrothermal quartz-cassiterite and sulfide-cassiterite veins. Cassiterite is stable in zones of oxidation and surface weathering; with the destruction of primary deposits, it accumulates in placers. In the USSR, cassiterite deposits are found in the northeast in Primor’e, in Middle Asia, and in the Kazakh SSR. Abroad, it is found in Malaysia, Thailand, Indonesia, the People’s Republic of China, Bolivia, Nigeria, and elsewhere. Cassiterite is the chief ore for obtaining tin.

A. B. PAVLOVSKII

cassiterite

[kə′sid·ə‚rīt]
(mineralogy)
SnO2 A yellow, black, or brown mineral that crystallizes in the tetragonal system in prisms terminated by dipyramids; the most important ore of tin. Also known as tin stone.
References in periodicals archive ?
The illustrated samples bearing cassiterite and yazganite minerals (Figures 4 & 5) come from the edges of fissures in the porphyric pyroxene andesitic rocks at Senir Sirti.
For a description of the complex corruption and intimidation related to, as well as harrowing experience of miners at, cassiterite mining operations at the Bisie mine in North Kivu province in the DRC, see generally Schrank, supra note 106.
The recent inclusion of coltan and cassiterite in the DRC's EITI reporting is a step in the right direction.
Yet, besides these useful attributes lies the fact that the coltan trade based in eastern DRCongo is one of the various mineral trades--including gold, cassiterite, wolframite and diamonds--whose associated million-dollar illegal trafficking has served to brutally destabilise eastern Congo and fuel the ongoing conflict in which an estimated 5 million deaths have occurred since 1996.
2) "[It] is awash with gold, diamonds, and metals such as cassiterite and coltan used to weld small pieces together in electronics.
Clinton addressed the question of the trade in minerals such as cassiterite and coltan, which are dug up in eastern Congo for use in consumer electronics such as mobile phones and whose sale funds armed groups in the region.
The resulting journey the tin (which is mined as cassiterite and yields tin after smelting) takes as it makes its way into everything from video games to TVs is wreaking havoc with consumer electronics firms intent on following best practices for corporate humanitarianism.
The Antonov cargo aircraft that crahed was flying cassiterite and other valuable minerals exploits desperately poor local people who work in treacherous mines for low pay and can fuel instability and violence as businessmen and militias vie for control of resources and revenues.
For example, this has been the case in Angola with diamonds and oil and in the DRC with the exploitation of copper, cobalt, diamonds, gold, coltan, coffee, timber, niobium, and cassiterite.
Topics include case studies of compositional discrimination in Hungarian volcanites, Scottish limestone, Russian cassiterite, and in an Italian volcanic fumarolic field, with other applications in studies canonical variate vector components and tertiary sandstone composition in an evaluation of the Dickinson model.
Existence of lootable resources: Congo's vast natural resources have long served as a cause for conflict: gold, tin, cobalt, coltan (used in mobile telephone manufacturing), cassiterite, diamonds, niobium, coffee, other crops, livestock, timber and wildlife (e.