Page:Radio-activity.djvu/580

Samarskite Niobate and tantalate of Primary constituent of
                  rare earths pegmatite dikes
                  Uranium 8-10%

Fergusonite Metaniobate and tantalate " "
                  of rare earths
                  Uranium 1-6%

Euxenite Niobate and titanate of " "
                  rare earths
                  Uranium 3-10%

Monazite Phosphate of the rare " "
                  earths, chiefly cerium
                  Uranium 0·3-0·4%