Board Thread:General Discussion/@comment-96.233.74.45-20140413040730/@comment-3146930-20140428052117

The weird white light looked similar to his Aura, but as I said in the DVD commentary they mention it is a hint to his Semblance. There is also a strange ringing sound that lasts for several moments after the punch and overlaps with the white glow he sees on his arm. This could just be how his Semblance appears, similar to how Pyrrha's Polarity appears in the form of a black glow. It is entirely possible that Jaune's Semblance and Aura have the same color glow.