Amulets are the most common artifact that holds a titan. Most of the titans held by Dante's team are held within amulets as are most of the Organizations titans. Amulets are usually shaped with a style that refers to its titan, along with a jewel set in its center.
Amulets have been hidden for thousands of years, The Huntik Foundtion and The Organization both are in search of these as the more they possess, the more power the faction has. Amulets of great value usually belong to famous figures of history, including Lancelot of Camelot and contain very powerful titans.