What is "ellsworthite"

Ellsworthite (Ca,U)(Ti,Nb,Ta)O(OH) is a rare earth mineral mostly found in the northern parts of North America. It is named after H. V. Ellsworth of the Canadian Geological Survey by Walker and Parsons. Ellsworthite is also known under the name {Betafite}. It is a very and rich mineral, which in fact makes it slightly radioactive. makes up about 17.1% of the mineral.