What is Xenotime-(Y)?
Xenotime-(Y) is a dense yttrium phosphate and an important rare-earth mineral, valued by collectors for sharp crystals and by geology for its ability to record trace-element history.
Mineralogy and structure
Reference formula: YPO4. Xenotime-(Y) is tetragonal with the ideal formula YPO4. COD 1011143 provides an exact structural reference. The xenotime group accepts substantial rare-earth substitution, so analysis matters. Xenotime-(Y) is classified with phosphates and has tetragonal crystal symmetry. Typical hardness is 4–5 on the Mohs scale and specific gravity is approximately 4.4–4.7.
Colour, lustre and habit
Typical colours include yellow, yellow-brown, brown, grey, greenish brown. The usual prismatic, pyramidal, granular habit and vitreous, resinous, adamantine lustre help describe a specimen, but colour alone is not diagnostic.
Formation and notable localities
Xenotime-(Y) forms in or is associated with granitic pegmatites, high-grade metamorphic rocks, alkaline complexes and heavy-mineral placers. Important documented localities include Brazil, Norway, Sweden, Madagascar, Russia, the United States and Australia.
The rare-earth phosphate collectors recognise
Xenotime-(Y) combines collector appeal with real geochemical value. Sharp brown-yellow crystals in a pegmatite or placer tell a strong story when provenance is documented.
Collecting and care
Dense and brittle: protect crystals from impact and acids, and keep locality and analytical data with the specimen.
