Silver's emerald: White

Silver travels (in this pic, with Blaze), through Dusty Desert to this tune. www.youtube.com/watch?v=kCAeRQ… It sounds like a mix of anguish and vengefulness. The former because Sonic is dead, and the latter because Silver is mythed about being tricked to try and kill Sonic twice. The white emerald shows he wants to make peace with Sonic and put things right.

Also, the glows are coming from ponyfied Silver's and Blaze's horns, so don't get that mixed up with the emerald's colour.