Xenotime
“Heavy rare earth phosphate timekeeper”
Xenotime is a yttrium phosphate mineral that preferentially incorporates the heavy rare earth elements (Dy, Er, Yb) into its crystal structure. Like its cousin monazite, it contains uranium and thorium, making it valuable for geochronology — but xenotime specializes in dating different geological conditions.
yttrium phosphate (YPO₄) with heavy rare earth elements
Iveland (Norway), Minas Gerais (Brazil), Llallagua (Bolivia), Madagascar, Western Australia (heavy mineral sands), Alpine veins
4-5
Xenotime's name comes from the Greek 'xenos' (stranger) and 'timé' (honor) — an ironic name meaning 'vain honor' because it was initially mistaken for a new element before being identified as a yttrium compound.
Test Your Knowledge
How does xenotime complement monazite in geochronological studies of metamorphic rocks?
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