An improved rupture disk assembly and methods and apparatuses for forming a rupture disk are disclosed. The rupture disk assembly includes a rupture disk having a flange connected to a dome-shaped rupturable portion by a transition area. The rupturable portion includes a structural apex formation at or near the apex of the dome and is configured to rupture when exposed to a fluid having a predetermined pressure. Preferably, a safety member is disposed adjacent the rupture disk. The safety member includes a hinge about which the disk bends when the disk ruptures. The present invention is also directed to an apparatus and method for consistently, accurately, and repeatably forming a structural apex formation in a rupture disk before the formation of to the rupture disk dome, during the formation of the rupture disk dome, and after the formation of the rupture disk dome.