Formula: YPO4 Tetragonal
Description: Xenotime-(Y) is a rare accessory mineral generally found in complex pegmatites. It resembles zircon in physical appearance and may be mistaken for it. It is noticeably softer than zircon, however.
MARATHON COUNTY: Xenotime-(Y) has been reported as yellow to brown crystals up to 1 mm in diameter in pegmatites of the Nine Mile pluton, such as are exposed in the “rotten granite” quarries south of Rib Mountain (sec. 19 and 20 T.28N. R.7E.) (Falster, 1987).
– Xenotime-(Y) has been reported in the pegmatites at Wimmer Pit #3, south of Rib Mountain. (NW sec. 19 T.28N R7E) (Buchholz, 1999b). It is fairly abundant, but difficult to distinguish from associated zircon.
– Xenotime-(Y) occurs as light brown to yellow xls. at the Koss Pit, (SW sec. 2 T27N R.5E) south of Rib Mountain. (Buchholz, Falster and Simmons, 1999).
– Xenotime-(Y) occurs at the Red Rock Granite North Pit (along Spring Brook Road) and the Ladick Quarry (sec. 19 and 20 T. 27N. R.6E.) (Buchholz and Simons, 2002).
– Xenotime-(Y) was found in an excavation for a house foundation, on the west side of 108th Avenue, Stettin. It was associated with siderite (replaced by iron oxides, brookite and zircon. (Tom Buchholz, 1997, pers. comm.).
WOOD COUNTY: Xenotime-(Y) was recovered in heavy mineral separates from foliated tonalite quarried near Honey Island (NE NW sec. 6 T., 25 N. R.5E.) (Van Wyck, 1995).
– Xenotime-(Y) is an accessory in the granite exposed in the Haske quarry in Sec. 25 T.24N. R.2E (Buchholz, et. al., 2005a.).