Yeah, I like that line too, if you ponder on it for too long however it starts to lack in sense.. i.e. What is a rebelious diamond? also the 'sun' is a star, so obviously its going to shine like a star... In summary: the lyrics are beautiful but look no further.
I guess the poetry lies in the fact that it only seems to make sense. But also diamonds against a black cloth look like stars. The rebel bit evokes the idea that they don't want to be a part of the big light, they want to shine on their own.