Xenotime-(Y) Locality: Mt Malosa, Zomba District, Malawi (Locality at mindat.org) Picture width 1 mm. Collection and photograph Christian Rewitzer Pale brown xe — Photo: Christian Rewitzer · CC BY-SA 3.0
Xenotime-(Y)
Also known as: Xenotime.
Xenotime is a rare-earth phosphate mineral, the major component of which is yttrium orthophosphate (YPO4). The phosphate ions are described by a tetrahedral shape and coordinate to the center Y3+ metal ion in a way that closely resembles the structure of zircon (ZrSiO4). It forms a solid solution series with chernovite-(Y) (YAsO4) and therefore may contain trace impurities of arsenic, as well as silicon dioxide and calcium.
Intro adapted from Wikipedia (CC BY-SA).
Xenotime-(Y) is an IMA-recognized mineral species in the phosphate class, with the chemical formula Y(PO₄).
It crystallizes in the tetragonal crystal system (space group I4_1/amd). It is a member of the Zircon structural group.
Key properties: Mohs hardness 4–5; specific gravity 4.4–5.1; typically brown or yellow or gray or red or orange; white streak; Vitreous to resinous luster; optically uniaxial.
IMA symbol Xtm-Y, IMA status: approved, named in 1832.
An accessory mineral in alkalic to granitic rocks, well-developed in associated pegmatites; in gneiss and Alpine veins; a common detrital mineral in placers.
It is found associated with Zircon, monazite, rutile, anatase, brookite, hematite, ilmenite, gadolinite, allanite, apatite, yttrotantalite, thorite.
Its name comes from the Greek for vain and honor, as the contained yttrium had been mistaken for a new element.
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