You need an insane amount of energy to fuse atoms into heavier elements, where not even a supernova is enough to produce. It's speculated that kilonovas (which is the collision of two neutron stars, or a neutron star with a black hole) are responsible to creating the heavy metals and why they are so rare in the earth's crust.

You need an insane amount of energy to fuse atoms into heavier elements, where not even a supernova is enough to produce. It's speculated that killonovas (which is the collision of two neutron stars) are responsible to creating the heavy metals and why they are so rare in the earth's crust.