Xenotime


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xenotime

[′zēn·ə‚tīm]
(mineralogy)
Y(PO4) A tetragonal mineral of varying color, consisting of yttrium phosphate.

Xenotime

 

a mineral; yttrium phosphate, YPO4 (V2O3 ~ 63.1 percent). Xenotime always contains rare earths, sometimes ThO2, UO2 (up to 5 percent), ZrO2 (up to 3 percent), and others. It crystallizes in the tetragonal system, forming pyramidal or prismatic crystals; it is isostructural with zircon. Xenotime is light brown or reddish brown in color. It has a hardness of 4–5 on the mineralogical scale and a density of 4,450-4,590 kg/ m3. It occurs in granites and pegmatites in the form of granules or crystals ingrown into feldspar or quartz; it also occurs in alluvial deposits. Xenotime is closely associated with monazite and zircon.

The best-known deposits of xenotime are the pegmatite and alluvial deposits of Brazil (Minas Geraes) and the pegmatites of Norway (Hitterö, near Arendal, and Kragerö in Telemark) and Sweden (Ytterby). In the USSR, xenotime is found in the pegmatites of Karelia.

References in periodicals archive ?
The REE in clastic sediments are concentrated in detrital accessory minerals, mainly phosphates (notably monazite and apatite for LREE and xenotime for HREE), minor silicates (notably allanite, titanate, and zoisite for LREE, garnet and zircon for HREE), and adsorbed to clays (especially HREE).
Harrison, Carlos, and Montel provide the opening chapter on U-Th-Pb dating of apatite, monazite and xenotime and provide a good overview.
4] which suggests that the incorporation of Pb in the monazite structure, and the lack of Pb incorporation in the xenotime structure orthophosphates, is related to this change in structure.
Accessory minerals are apatite, zircon, ilmenite, rarely magmatic andalusite, cordierite, monazite, xenotime and allanite.
This leaching process and Stromberg's xenotime mineralogy could potentially result in a more direct processing route to a valuable REE intermediate/carbonate material with lower capital expenditure.
Zr for zircon, Ti for rutile or anatase, B for tourmaline, Y for xenotime (Mitchell 1975; Chittleborough et al.
Xenotime mineralogy theoretically offers simple processing/development routes (see TUC ASX Announcement dated 12 November 2011).
Inclusions observed include rutile, titanite, ilmenite, xenotime, diopside, quartz, calcite, gypsum, tremolite (Barot and Boehm, 1992), and graphite (Dunn, 1975).
From a petrographic point of view, the main granite facies was classified as a weakly altered alkaline-feldspar granite with two micas, muscovite being dominant over biotite The accessory mineral association is very complex: ilmenite, zircon, monazite, xenotime, apatite, uraninite, cassiterite and primary sulphides (Perez del Villar and de la Cruz, 1989).
The wide-range of gemstones including sapphires from Kashmir, emeralds from Swat, rubies from the northern areas and pink topazes from Katlang, Mardan, and good quality zircon, different varieties of quartz, aquamarine, tourmaline, sphene, spinel, zoisite apatite, epidote, morganite, garnet, scapolite, clino zoisite, xenotime, bastnaesite, peridot, nephrite, serpentine, agate, diopside, pargasite, amethyst, scheelite, pollucite, chrome diopside and kunzite are found in mountainous belt from South Waziristan to Chitral, makes the country significant in the mineral world.
Not surprisingly, the most impressive entries are those for the alpine minerals: grossular, diopside, epidote, quartz, cafarsite, vesuvianite, titanite, xenotime and many others, which have received a more extensive treatment and are illustrated by full-page plates of specimen photos.