Physically speaking, the Hammer Parts look identical to Amy's Hammer, except that they come in a different size.
In Sonic Boom: Fire & Ice, there are a total of sixty Hammer Parts which are hidden in the game's levels. The five first islands in the game hold twelve Hammer Parts each, which are hidden in the adventure levels. Each of the four adventure levels on each island in the game holds three Hammer Parts, each of which can be collected by opening an item capsule resembling a golden bubble with a Hammer Part inside it. These capsules break when touched and can be targeted with the Homing Attack.
When obtained, the Hammer Parts can be brought to Amy's House to be put on display in Amy's display case. For every tenth Hammer Part the player recovers, they will unlock a new skin for Amy's Hammer in gameplay which can be equipped and viewed in Amy's House.
List of hammers