Because americium isotopes have not very long half lives any possible (probable) primordial americium disappeared many time ago.
As all radioactive elements, isotopes of americium continuously decay.
Americium-241 has an alpha decay associated with gamma.
For example americium-241 decay to neptunium-237 and americium-243 decay to neptunium-239.
The alpha decay of americium-241 produce neptunium-237.
Americium can change into neptunium through a process called alpha decay. During alpha decay, an alpha particle (helium nucleus) is emitted from the nucleus of the americium atom, resulting in the transformation of the americium atom into a neptunium atom.
The radioactive decay of americium 241 is by alpha disintegration; the disintegration of radioactive krypton isotopes is by beta particles emission.
The decay products of americium-241 include neptunium-237, plutonium-241, and various isotopes of neptunium, plutonium, and uranium. These decay products are formed as americium-241 undergoes alpha decay and transforms into new elements through a series of radioactive decays.
Americium-244 undergoes beta decay: 95244Am --> 96244Cm + -10e where -10e is a negative beta particle or electron.
The half life of americium 241 is 432,2 years.
Americium-243 might undergo alpha decay to become neptunium-239, and here is that equation: 95243Am => 93239Np + 24He++ The americium-243 has undergone transmutation to become neptunium-239, and the alpha particle, which is a helium-4 nucleus, can be seen on the tail end of the equation.
Emitting alpha particles Am-241 decay to Np-237.
Americium is a transuranic radioactive chemical element that has the symbol Am and atomic number 95.Its most common isotopes are 241Am and 243Am.241Am decays by emission of an Alpha particle to 237Np; the half-life of this decay is 432.2 years. 241Am95 (by Alpha decay) ------ 237Np93Refer to link below for more information.