real pearls would feel kinda heavy for their size, would feel kinda rough against your teeth, like if you rub them on the front of your front teeth. they'd have a slight gritty feeling. painted plastic would flake off, and unless the dye is really strong, it would still flake abit on real pearls, so that's not really a good measure. real ones wouldn't be perfectly round either (if they are, they're freaking expensive to buy!) they'd be wobbled, a lot or ever so slightly. i'm sure there are more ways, but these are the ways i use, and even then i'm wrong sometimes because i'm not totally versed in teh ways of pearls yet. i'm getting there. boy this is a big post >.<