Mmm, yes and no. It's not an exact science or anything, but more so the ability to understand the environment in which the rock is originating from. This can include not only typical reef structures from it's native area, common macro and micro life from that region, as well as climate. Which type of rock are you lookin for specifically? Let me know and I can let you know what to look for to identify it. If you'd just like me to cover the basics on all the common live rock, I can do that for you too. Just let me know.