Dark brown lustrous grain of samarskite-(Y) with quartz and potassium feldspar. Haske quarry, Wood County. Field of view is 2.5 mm left to right. Tom Buchholz specimen. Dan Behnke image.
Formula: (Y, Fe3+,Fe2+,U, Th, Ca)2(Nb,Ta)2O8 Orthorhombic
Description: Samaskite refers to a group of rare oxides found generally as black resinous masses in ganitc pegmastites. The decay of radioactive elements in them often renders them metamict.
MARATHON COUNTY: Samarskite-(Y) was identified as patches in miarolitic granite in the Koss Pit (Tom Buchholz, personal communication).
WOOD COUNTY: Samarskite-(Y) was identified as tiny grains in granite at the Haske Quarry, SW SE sec. 25 T24N R.2E. (Tom Buchholz, personal communication).
Properties of minerals 