First, be sure they are real pearls. While we usually think "akoya" when we see perfectly round pearls, imitations are also completely round.
Try rubbing 2 of the pearls together gently, or rubbing one pearl against the edge of your front tooth. Is it gritty feeling, or do they glide smoothly?
Real pearls feel gritty; imitation pearls glide smoothly.
Then, look at the clasp. Is it marked as gold, or gold colored base metal? Akoya pearls would not usually be strung with a base metal clasp.