Stony iron meteorites are thought to have originated at the core-mantle boundary of differentiated asteroids, where the metallic core meets silicated rocks. They were then shattered into space as the result of another meteorite impact, where they remained until they fell upon Earth. The proportion of silicates to metal is about 50% for each. However, it is not uncommon to randomly see stony-iron meteorites with a higher content of one than the other.