The first actinides to be discovered were Uranium by Klaproth in 1789 and Thorium by Berezelius in 1829, but most of the Actinides were man-made products of the 20th century.It is a phosphate ore that contains great amounts of Lanthanides in it. The main Uranium ore is U3O8 and is known as pitchblende, because it occurs in black, pitch-like masses.Monazite is the principle Thorium ore.All elements past Uranium are man-made.