Uranpyrochlore (of Hogarth 1977), also known as ellsworthite or betafite (Ca,U)2(Ti,Nb,Ta)2O6(OH), is a rare earth mineral mostly found in the northern parts of North America.

It is a uranpyrochlore and is named after Hardy V. Ellsworth of the Canadian Geological Survey by Walker and Parsons.

[3] It is a very uranium- and thorium- rich mineral, which in fact makes it slightly radioactive.

Ellsworthite is a thorium-bearing mineral that is found mostly in Canada and Alaska.

[2] Ellsworthite has complex hydrous oxides of niobium, tantalum, sodium, calcium, with hydroxyl and fluorine; it may contain as much as 17% uranium.