I don't like it. Rightly or wrongly, based on I don't know quite what, I think of Raven and Ebony as names that would as a pp said feel a bit discordant on a white child. Although I take the point that a Violet is not going to be Violet! Ruby is not going to be red. Hmm. Maybe I've talked myself in to thinking it's ok. Only ok though.
There's a name Eben and I like that.