Editing Cassiterite

{{Short description|Tin oxide mineral}}
{{Infobox mineral
| name        = Cassiterite
| category    = [[Oxide minerals]]
| boxwidth    =
| boxbgcolor  =
| image       = 4447M-cassiterite.jpg
| imagesize   =
| caption     = Cassiterite with [[muscovite]], from Xuebaoding, Huya, Pingwu, Mianyang, Sichuan, China (size: 100 x 95 mm, 1128 g)
| formula     = SnO<sub>2</sub>
| IMAsymbol=Cst<ref>{{Cite journal|last=Warr|first=L.N.|date=2021|title=IMA–CNMNC approved mineral symbols|journal=Mineralogical Magazine|volume=85|issue=3|pages=291–320|doi=10.1180/mgm.2021.43|bibcode=2021MinM...85..291W|s2cid=235729616|doi-access=free}}</ref> 
| molweight   =
| strunz      = 4.DB.05
| system      = [[Tetragonal]] 
| class       = Ditetragonal dipyramidal (4/mmm) <br/>[[H-M symbol]]: (4/m 2/m 2/m)
| symmetry    = ''P4''<sub>2</sub>/mnm
| unit cell   = a = 4.7382(4)&nbsp;Å, <br/>c = 3.1871(1)&nbsp;Å; Z&nbsp;=&nbsp;2
| color       = Black, brownish black, reddish brown, brown, red, yellow, gray, white; rarely colorless 
| habit       = Pyramidic, prismatic, radially fibrous botryoidal crusts and concretionary masses; coarse to fine granular, massive
| twinning    = Very common on {011}, as contact and penetration twins, geniculated; lamellar
| cleavage    = {100} imperfect, {110} indistinct; partings on {111} or {011}
| fracture    = Subconchoidal to uneven
| tenacity    = Brittle
| mohs        = 6–7
| luster      = Adamantine to adamantine metallic, splendent; may be greasy on fractures
| refractive  = n<sub>ω</sub> = 1.990–2.010 n<sub>ε</sub> = 2.093–2.100
| opticalprop = Uniaxial (+)
| birefringence = δ = 0.103
| pleochroism = Pleochroic haloes have been observed. Dichroic in yellow, green, red, brown, usually weak, or absent, but strong at times
| streak      = White to brownish
| gravity     = 6.98–7.1
| density     =
| melt        =
| fusibility  = infusible
| diagnostic  =
| solubility  = insoluble
| diaphaneity = Transparent when light colored, dark material nearly opaque; commonly zoned
| other       =
| references  = <ref>[https://www.mineralienatlas.de/lexikon/index.php/MineralData?mineral=Cassiterite Mineralienatlas]</ref><ref name=Handbook>{{cite web |last1=Anthony |first1=John W. |last2=Bideaux |first2=Richard A. |last3=Bladh |first3=Kenneth W. |last4=Nichols |first4=Monte C. |title=Cassiterite |url=http://www.handbookofmineralogy.org/pdfs/cassiterite.pdf |website=Handbook of Mineralogy |publisher=Mineral Data Publishing |access-date=19 June 2022 |date=2005}}</ref><ref name=Mindat>{{mindat|id=917|title=Cassiterite}}</ref><ref name=Webmin>[http://webmineral.com/data/Cassiterite.shtml Webmineral]</ref><ref name=Klein>{{cite book |last1=Hurlbut |first1=Cornelius S. |last2=Klein |first2=Cornelis |year=1985 |title=Manual of Mineralogy |edition=20th |publisher=John Wiley and Sons |location=New York |pages=[https://archive.org/details/manualofmineralo00klei/page/306 306–307] |isbn=0-471-80580-7 |url-access=registration |url=https://archive.org/details/manualofmineralo00klei/page/306 }}</ref>
}}
'''Cassiterite''' is a [[tin]] [[oxide mineral]], [[tin dioxide|SnO<sub>2</sub>]].  It is generally [[Opacity (optics)|opaque]], but it is translucent in thin crystals. Its [[Lustre (mineralogy)|luster]] and multiple crystal faces produce a desirable gem. Cassiterite was the chief tin [[ore]] throughout [[Tin sources and trade in ancient times|ancient history]] and remains the most important source of tin today.

==Occurrence==
[[File:Cassiterite.jpg|thumb|left|Cassiterite [[bipyramids]], edge length {{circa|30 mm}}, [[Sichuan]], China]]
[[Image:Cassiterite - Blue Tier tinfield, Tasmania, Australia.jpg|thumb|left|Close up of cassiterite crystals, Blue Tier tinfield, [[Tasmania]], Australia]]

Most sources of cassiterite today are found in [[alluvium|alluvial]] or [[placer mining|placer]] deposits containing the weathering-resistant grains. The best sources of primary cassiterite are found in the tin mines of [[Bolivia]], where it is found in crystallised [[hydrothermal]] veins. [[Rwanda]] has a nascent cassiterite mining industry. Fighting over cassiterite deposits (particularly in [[Walikale]]) is a major cause of the conflict waged in eastern parts of the [[Democratic Republic of the Congo]].<ref>{{cite news |url=http://www.newsvine.com/_news/2008/11/01/2061627-mining-for-minerals-fuels-congo-conflict|title=Mining for minerals fuels Congo conflict |last=Watt |first=Louise |agency=[[Associated Press]] |date=2008-11-01 |access-date=2009-09-03|work=Yahoo! News |publisher=[[Yahoo!|Yahoo! Inc]]}}</ref><ref>{{cite news
 | last = Polgreen
 | first = Lydia
 | title = Congo's Riches, Looted by Renegade Troops
 | work=[[The New York Times]]
 | date = 2008-11-16
 | url = https://www.nytimes.com/2008/11/16/world/africa/16congo.html?pagewanted=1&_r=1&th&emc=th
 | access-date = 2008-11-16}}</ref>  This has led to cassiterite being considered a [[conflict mineral]].

Cassiterite is a widespread minor constituent of [[igneous rocks]]. The Bolivian veins and the 4500 year old workings of [[Cornwall]] and [[Devon]], [[England]], are concentrated in high temperature [[quartz]] veins and [[pegmatite]]s associated with [[granite|granitic]] [[Intrusive rock|intrusive]]s. The veins commonly contain [[tourmaline]], [[topaz]], [[fluorite]], [[apatite]], [[wolframite]], [[molybdenite]], and [[arsenopyrite]]. The mineral occurs extensively in [[Cornwall]] as surface deposits on [[Bodmin Moor]], for example, where there are extensive traces of a hydraulic mining method known as ''streaming''. The current major tin production comes from placer or alluvial deposits in [[Malaysia]], [[Thailand]], [[Indonesia]], the [[Maakhir]] region of [[Somalia]], and [[Russia]]. [[Hydraulic mining]] methods are used to concentrate mined ore, a process which relies on the high [[specific gravity]] of the SnO<sub>2</sub> ore, of about 7.0.

==Crystallography==
[[Image:Rutile-unit-cell-3D-balls.png|thumb|left|Crystal structure of cassiterite]]

[[Crystal twinning]] is common in cassiterite and most aggregate specimens show crystal twins. The typical twin is bent at a near-60-degree angle, forming an "elbow twin". [[Botryoidal]] or reniform cassiterite is called ''wood tin''.

Cassiterite is also used as a [[gemstone]] and collector specimens when quality crystals are found.

[[File:Cassiterite-43265.jpg|thumb|upright|left|Stalactitic-botryoidal, banded, "wood tin" cassiterite, {{cvt|5.0|x|4.9|x|3.3|cm}}, [[Durango]], Mexico]]

==Etymology==
The name derives from the [[Greek language|Greek]] κασσίτερος (''[[Transliteration|transliterated]] as "kassiteros")'' for "tin".<ref name=":0">{{Cite web |title=Defininiton of κασσίτερος |url=https://logeion.uchicago.edu/%CE%BA%CE%B1%CF%83%CF%83%CE%AF%CF%84%CE%B5%CF%81%CE%BF%CF%82 |access-date=2024-11-07 |website=logeion.uchicago.edu}}</ref> Early references to κασσίτερος can be found in [[Homer]]'s [[Iliad]], such as in the description the [[Shield of Achilles|Shield of Achillies]]. For example, the passage in book 18 chapter 610: <blockquote>αὐτὰρ ἐπεὶ δὴ τεῦξε σάκος μέγα τε στιβαρόν τε,

610τεῦξ᾽ ἄρα οἱ θώρηκα φαεινότερον πυρὸς αὐγῆς,

τεῦξε δέ οἱ κόρυθα βριαρὴν κροτάφοις ἀραρυῖαν

καλὴν δαιδαλέην, ἐπὶ δὲ χρύσεον λόφον ἧκε,

τεῦξε δέ οἱ κνημῖδας ἑανοῦ κασσιτέροιο.<ref>{{Cite web |title=Homer, Iliad, Book 18, line 590 |url=https://www.perseus.tufts.edu/hopper/text?doc=urn:cts:greekLit:tlg0012.tlg001.perseus-grc1:18.610 |access-date=2024-11-07 |website=www.perseus.tufts.edu}}</ref></blockquote>Translated as: <blockquote>then wrought he for him a [[Corslet|corselet]] brighter than the blaze of fire, and he wrought for him a heavy helmet, fitted to his temples, a fair helm, richly-dight, and set thereon a crest of gold; and he wrought him [[Greave|greaves]] of pliant tin. But when the glorious god of the two strong arms had fashioned all the armour<ref>{{Cite web |title=ToposText |url=https://topostext.org/work/2#18.61 |access-date=2024-11-07 |website=topostext.org}}</ref></blockquote>[[A Greek–English Lexicon|Liddell-Scott-Jones]] suggest the etymology to be originally [[Elamite language|Elamite]]; citing the [[Babylonia|Babylonian]] '''''kassi-tira,''''' hence the [[sanskrit]] '''''kastīram'''''.<ref name=":0" /> However the [[Akkadian language|Akkadian]] word (the [[lingua franca]] of the [[Ancient Near East]], including Babylonia) for tin was "''anna-ku''"<ref>{{Cite journal |last=Læssøe |first=Jørgen |date=1970-01-01 |title=Akkadian annakum: "tin" or "lead"? |url=https://journals.uio.no/actaorientalia/article/view/5285 |journal=Acta Orientalia |volume=24 |pages=10 |doi=10.5617/ao.5285 |issn=1600-0439|doi-access=free }}</ref> (cuneiform: 𒀭𒈾<ref>{{Cite journal |last=Dossin |first=G. |date=1970 |title=La Route De L'étain En Mésopotamie Au Temps De Zimri-Lim |url=https://www.jstor.org/stable/23283408 |journal=Revue d'Assyriologie et d'archéologie orientale |volume=64 |issue=2 |pages=97–106 |jstor=23283408 |issn=0373-6032}}</ref>). [[Roman Ghirshman]] (1954) suggests, from the region of the [[Kassites]], an ancient people in west and central [[Iran]]; a view also taken by J D Muhly.<ref>{{Cite journal |last=Muhly |first=James D. |date=1985-04-01 |title=Sources of Tin and the Beginnings of Bronze Metallurgy |url=https://www.journals.uchicago.edu/doi/10.2307/504330 |journal=American Journal of Archaeology |language=en |volume=89 |issue=2 |pages=275–291 |doi=10.2307/504330 |jstor=504330 |issn=0002-9114|url-access=subscription }}</ref> There are relatively few words in [[Ancient Greek]] at begin with "κασσ-";<ref>{{Cite book |last=CLASSICS |first=FACULTY OF |url=https://books.google.com/books?id=0VndzQEACAAJ |title=CAMBRIDGE GREEK LEXICON. |date=2021 |publisher=CAMBRIDGE University Press |isbn=978-0-521-82680-8 |pages=746–7 |language=en}}</ref> suggesting that it is an [[ethnonym]].<ref name=":1" /> Attempts at understanding the [[etymology]] of the word were made in [[Classical antiquity|antiquity]], such as [[Pliny the Elder]] in his [[Natural History (Pliny)|Historia Naturalis]] (book 34 chapter 37.1):<blockquote>"''White lead (tin) is the most valuable; the Greeks applied to it the name '''cassheros'''''".<ref>{{Cite web |title=ToposText |url=https://topostext.org/work/153#34.47.1 |access-date=2024-11-07 |website=topostext.org}}</ref></blockquote>

And [[Stephanus of Byzantium]] in his ''[[Stephanus of Byzantium|Ethnica]]'' states: <blockquote>"Κασσίτερα νησοσ εν τω Ωκεανω, τη [[Indus Valley Civilisation|Ίνδικη]] προσεχης, ως Διονυσιοσ εν Βασσαρικοισ. Εξ ης ο [[tin|κασσίτερος]]."<ref name=":1">{{Cite book |url=https://archive.org/details/STEPHANUSBYZANTIUSMargaretheBillerbeckStephaniByzantiiEthnicaKO.BYMARGARETHEBILLERBECK/page/237/mode/2up |title=STEPHANUS BYZANTIUS Margarethe Billerbeck] Stephani Byzantii Ethnica, K O. BY MARGARETHE BILLERBECK |date=2014 |pages=56–7}}</ref></blockquote>Which can be translated as: <blockquote>''Kassitera, an island in the [[Persian Gulf|ocean]], neighbouring [[Indus Valley Civilisation|India]], as [[:de:Dionysios_(Epiker)|Dionysius]] states in the [[:de:Dionysios_(Epiker)|Bassarika]]. From there comes [[tin]].''</blockquote>

== Use ==
It may be primarily used as a raw material for [[tin]] extraction and smelting.

==References==
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{{reflist|25em}}

==External links==
{{Commons category|Cassiterite}}

{{Ores}}

{{Authority control}}

[[Category:Tin minerals]]
[[Category:Oxide minerals]]
[[Category:Tin mining]]
[[Category:Rutile group]]
[[Category:Tetragonal minerals]]
[[Category:Minerals in space group 136]]