Well, since it is proven that its not plastic, because of the dink sound, i can conclude that it must be pretty dense. But, when doing my research while i beat my wife, I noticed it had a vibrating effect. Players in a certain radius notice the vibrations because of the camera shaking. Thanks to my handydandy bs machine, i can conclude that the hammer's density is about 12 g/cm squared.
Thanks for stroking my science rod, and remember to join my army of 7 million kids.
Sources: my ass