Sam's Allspark Shard detailed replica in TF ROTF. Metal prints will give it a satisfying weight when being held. Antique Silver will look most like the prop. Might as well become a family heirloom! Check out
TF AllSpark Shard w/ Hole if you want to use it as a pendant or tie it to a keychain, etc.
Plastic material prints are available if you want to give it your own finish.