i have to disagree with thomas on this one, i do not believe in scrubbing it, espcially in a new tank, it wont hurt the cycle one bit to use that rock without doing so.
IMO, scrubbin only gets rid of alot of garbage, some of which may have a had a small cahnce of surviving or coming back.
however, as was said, if a new tank with no life in it and only sw and sand, jsut add the rock and wait it out.
good luck
as for identifying, all over the web, good descriptions and pics here can turn up lots of answers. Esp if you can provide pics, most of us have or have seen the life you may or may not have. Every once inn a while someone will thro us a curve ball but not too often.