Chaos Diamonds 3 - page 346

This one page is the entire reason why I designed Tails' gauntlet with that bigass spike on it. It was a tool to not only guard the Diamond of Revenge, but to dig the Diamond of Will clean out of Sonic's forehead.

The script called for Sonic to simply be beaten to a pulp so bad that the Diamond fell out of Sonic. But in my mind, for the Diamond to work with a host yet still be exposed, it would fuse itself so thoroughly with the host that it would have to be physically removed. It also ties itself nicely into page 225, where Rouge kind of implies that the Diamonds COULD be ripped out with enough force.