Editing Gadolinium (section)

==Occurrence==
[[File:Gadolinitas.jpg|thumb|Gadolinite]]
Gadolinium is a constituent in many minerals, such as [[monazite]] and [[bastnäsite]]. The metal is too reactive to exist naturally. Paradoxically, as noted above, the mineral [[gadolinite]] actually contains only traces of this element. The abundance in the Earth's crust is about 6.2&nbsp;mg/kg.<ref name="Greenwood" /> The main mining areas are in China, the US, Brazil, Sri Lanka, India, and Australia with reserves expected to exceed one million tonnes. World production of pure gadolinium is about 400 tonnes per year. The only known mineral with essential gadolinium, [[lepersonnite-(Gd)]], is very rare.<ref>{{cite journal | last1 = Deliens | first1 = M. | last2 = Piret | first2 = P. | year = 1982 | title = Bijvoetite et lepersonnite, carbonates hydrates d'uranyle et des terres rares de Shinkolobwe, Zaïre | url = | journal = Canadian Mineralogist | volume = 20 | issue = | pages = 231–38 }}</ref><ref>{{cite web|url=https://www.mindat.org/min-2378.html |title=Lepersonnite-(Gd): Lepersonnite-(Gd) mineral information and data |website=Mindat.org |access-date=4 March 2016}}</ref>