Is the only way for you to describe girl A from girl B to say that she is black, you racist?
Thanks for all the relevant info, by the way, like is she is shy or does she dress like a slut.
Instead of getting her number straight away, say something like "are you going to x party/goth nite?" and if she says 'yes' then make sure you go and meet her, get her number then.
If she says she doesn't know about said party, ask if she would like to know details, etc - this doesn't have to be a date - you could swap numbers this way. :/