Tom Udø (1972-2018) klarte å preparere ut dette krystall i en gruve i Frikstad, Iveland. Den ble fotografert montert på veggen av et monter i Toms utstilling. L — Photo: Ronald Werner · CC BY-SA 4.0
Gadolinite-(Y)
Also known as: Gadolinite.
Gadolinite, sometimes known as ytterbite, is a silicate mineral consisting principally of the silicates of cerium, lanthanum, neodymium, yttrium, beryllium, and iron with the formula (Ce,La,Nd,Y)2FeBe2Si2O10. It is called gadolinite-(Ce) or gadolinite-(Y), depending on the prominent composing element (Y if yttrium predominates, and Ce if cerium). It may contain 35.5% yttria sub-group rare earths, 2.2% ceria earths, as much as to 11.6% BeO, and traces of thorium. It is found in Sweden, Norway, and the US (Texas and Colorado).
Intro adapted from Wikipedia (CC BY-SA).
Gadolinite-(Y) is an IMA-recognized mineral species in the silicate class, with the chemical formula Y₂Fe²⁺Be₂O₂(SiO₄)₂.
It crystallizes in the monoclinic crystal system (space group P2_1/c). It is a member of the Gadolinite structural group.
Key properties: Mohs hardness 6.5–7; specific gravity 4.36–4.77; typically black or brown or green; Greenish gray streak; Vitreous to greasy luster; optically biaxial.
IMA symbol Gad-Y, IMA status: approved, named in 1802.
Found in granite and alkalic granite pegmatites.
It is found associated with Allanite, fluorite, fergusonite, yttrialite, chevkinite, zircon.
The name refers to the Finnish chemist, Johan Gadolin (1760–1852), who discovered yttrium.
Collections: Collector Favorites, Rare & Remarkable.