Not much is known about the Tomahawk Reflex Hammer aside from its effects.
When the hammer is tapped against a joint (such as the hinge of a door or a gate), it causes violent tremors in the attached material, which rapidly leads the material to shake itself to pieces.
Taylors (Tomahawk-style reflex hammers) are made of a triangular rubber head on a metal frame, and are the most widely-used form of reflex testers in the United States. They're used to gauge the human body's reflex action and detect neurological disorders by striking a tendon; the one just above the kneecap, for example. The artifact would presumably be the prototype.