Polycrase or polycrase-(Y) is a black or brown metallic complex uranium with formula: (Y,Ca,Ce,U,Th)(Ti,Nb,Ta)2O6. It is amorphous. It has a Mohs hardness of 5. It is radioactive due to its uranium content (around 6%). It occurs in granitic.
Polycrase forms a continuous series with the niobium rich rare earth oxide euxenite.
It was first described in 1870 at Rasvag , Hidra (Hittero) Island, Norway. It is found in Sweden, Norway, and the United States.