Editing Tellurium (section)

===Occurrence===
{{see also|Telluride mineral}}
[[File:Tellurium-89043.jpg|thumb|left|Native tellurium crystal on [[sylvanite]] ([[Vatukoula]], [[Viti Levu]], [[Fiji]]). Picture width 2 mm.]]

With an abundance in the Earth's [[crust (geology)|crust]] comparable to that of platinum (about 1&nbsp;μg/kg), tellurium is one of the rarest stable solid elements.<ref>{{Cite book|date=2002|url=https://books.google.com/books?id=g1Kb-xizc1wC&pg=PA396|page=396|title=A handbook of industrial ecology|first1 = Robert U.|last1 = Ayres|first2= Leslie|last2 = Ayres|publisher=Edward Elgar Publishing|isbn=1-84064-506-7}}</ref> In comparison, even [[thulium]] – the rarest of the stable [[lanthanide]]s – has crystal abundances of 500&nbsp;μg/kg (see [[Abundance of the chemical elements]]).<ref>{{Cite journal|doi=10.1103/RevModPhys.28.53|title=Abundances of the Elements|date=1956|last1=Suess|first1=Hans|last2=Urey|first2=Harold|journal=Reviews of Modern Physics|volume=28|issue=1|pages=53–74|bibcode=1956RvMP...28...53S}}</ref>

The rarity of tellurium in the Earth's crust is not a reflection of its cosmic abundance. Tellurium is more abundant than [[rubidium]] in the cosmos, though rubidium is 10,000 times more abundant in the Earth's crust. The rarity of tellurium on Earth is thought to be caused by conditions during preaccretional sorting in the solar nebula, when the stable form of certain elements, in the absence of [[oxygen]] and [[water]], was controlled by the reductive power of free [[hydrogen]]. Under this scenario, certain elements that form volatile [[hydride]]s, such as tellurium, were severely depleted through the evaporation of these hydrides. Tellurium and selenium are the heavy elements most depleted by this process.<ref name="Chemical" />

Tellurium is sometimes found in its native (i.e., elemental) form, but is more often found as the tellurides of [[gold]] such as [[calaverite]] and [[krennerite]] (two different [[polymorphism (materials science)|polymorph]]s of AuTe<sub>2</sub>), [[petzite]], Ag<sub>3</sub>AuTe<sub>2</sub>, and [[sylvanite]], AgAuTe<sub>4</sub>. The town of [[Telluride, Colorado]], was named in the hope of a strike of gold telluride (which never materialized, though gold metal ore was found). Gold itself is usually found uncombined, but when found as a chemical compound, it is often combined with tellurium.<ref name="CRC"/>

Although tellurium is found with gold more often than in uncombined form, it is found even more often combined as tellurides of more common metals (e.g. [[melonite]], NiTe<sub>2</sub>). Natural [[tellurite]] and [[tellurate]] minerals also occur, formed by the oxidation of tellurides near the Earth's surface. In contrast to selenium, tellurium does not usually replace sulfur in minerals because of the great difference in ion radii. Thus, many common sulfide minerals contain substantial quantities of selenium and only traces of tellurium.<ref>{{Cite book|chapter = Phase Relations in the Selenide Telluride Systems|pages =217–256| isbn = 978-90-5410-723-1|chapter-url =https://books.google.com/books?id=HUWRZecignoC&pg=PA217|publisher = Taylor & Francis|date = 1996|title = Geochemistry, mineralogy and genesis of gold deposits|first = I. Y.|last = Nekrasov}}</ref>

In the gold rush of 1893, miners in [[Kalgoorlie]] discarded a pyritic material as they searched for pure gold, and it was used to fill in potholes and build sidewalks. In 1896, that tailing was discovered to be [[calaverite]], a telluride of gold, and it sparked a second gold rush that included mining the streets.<ref>{{Cite book|title=The Earth: An Intimate History |last=Fortey |first=Richard |author-link=Richard Fortey |date=2004 |publisher=[[Harper Perennial]]<!-- presumably UK but not sure --> |isbn=978-0-00-257011-4 |page=230}}</ref>

In 2023 astronomers detected the creation of tellurium during collision between two neutron stars.<ref>{{Cite news |last=Sample |first=Ian |last2= |first2= |date=25 October 2023 |title=Creation of rare heavy elements witnessed in neutron-star collision |language=en-GB |work=The Guardian |url=https://www.theguardian.com/science/2023/oct/25/creation-of-rare-heavy-elements-witnessed-in-neutron-star-collision |access-date=26 October 2023 |archive-url=https://web.archive.org/web/20231026082650/https://www.theguardian.com/science/2023/oct/25/creation-of-rare-heavy-elements-witnessed-in-neutron-star-collision |archive-date=26 October 2023 |issn=0261-3077}}</ref>