Images
Formulae:
xenotime-(Y): Y(PO4)
xenotime-(Yb): Yb(PO4)
Phosphates, xenotime-(Y) forms a series with
xenotime-(Yb) and with
chernovite-(Y).
Zircon is an epitaxial mineral (Mindat)
Physical data for xenotime-(Y), which is by far the more common
mineral.
Specific gravity: 4.4 to 5.1
Hardness: 4 to 5
Streak: Pale brown, yellowish or reddish, white
Colour: Yellowish brown, reddish brown, light red, flesh-red, light green, grey, greyish white, wine-yellow. Colourless
to very light yellowish green, yellow or yellowish brown in transmitted light (Mindat)
Solubility: Very lightly attacked by acids
Environments:
Igneous environments
Pegmatites
Placer deposits
Xenotime is a rare phosphate of yttrium or
ytterbium that occurs as an accessory mineral in both acid and alkaline
rocks, and their associated pegmatites; it also occurs in mica,
gneiss
and Alpine veins, and is a common detrital mineral in placers (HOM, Webmin, Dana). Associated minerals include
zircon, monazite,
rutile, anatase,
brookite, hematite,
ilmenite, gadolinite,
allanite, apatite,
yttrotantalite, magnetite,
sillimanite, feldspar and
thorite (HOM, Dana, Mindat) and occasionally
fergusonite and columbite -
tantalite (Dana).
Localities
At Llallagua, Bolivia, xenotime has been found on monazite
(MinRec 37.2.160).
At Trimouns quarry, France, xenotime is found, rarely, in small vugs in crystallised
dolomite
and calcite
(MinRec 35.3.244).
At Erongo, Namibia, xenotime is associated with aquamarine,
fluorite and quartz. It has also
been found on metazeunerite from the uranium pocket
(MinRec 37.5.454).
In the river alluvium in the Grey River-Mawheraiti River area, North Westland, New Zealand, xenotime has been
found as a minor constituent of an assemblage that includes zircon,
ilmenite, spessartite -
almandine, monazite, and
tantalum-rich cassiterite
(AM 32.141).
At the type locality, Hidra, Flekkefjord, Norway, xenotime was found in a
granite
pegmatite associated with
gadolinite,
polycrase-euxenite,
allanite,
zircon, yttrotantalite and
thorite
(Dana).
At the Zagi mountain, Pakistan, xenotime, quartz and
microcline have been found together on a specimen, with all three minerals
having
inclusions of astrophyllite
(MinRec 35.3.219-220 ).
At Cheyenne Canyon, Pikes Peak, El Paso county, Colorado, USA, xenotime has been found with
fluocerite and bastnäsite
(Dana).
In the Manhattan schist, New York City, USA, xenotime and
monazite crystals have been found in a vein of coarse-grained grey
granite running through the local
mica
schist, and also in a
pegmatite vein in the
schist
(R&M 84.3.236-237 )
At Polk, McDowell, Burke county, North Carolina, USA, xenotime occurs as a detrital mineral in placer
gold deposits (Dana).
Back to Minerals