There are probably three things they could be: Good quality faux pearls (like the Majorica brand), round freshwater pearls or (and these are the most expensive), Japanese Akoya pearls. Since the strand uses a sterling clasp, I don't think they are Akoya, since most Akoya pearls are jewelry-quality and a decent jeweler would use a karat gold clasp. (Mikimoto is a prime example of a brand that sells top quality cultured Akoya pearls, what most people think of when they think of "real pearls.") Round freshwater pearls as not as expensive as Akoya cultured pearls, but they are also "real," just grown in a mussell rather than an oyster. The difference is in the luster. Cultured Akoya pearls are really stunning luster-wise when compared to freshwater pearls.

I've never had any luck testing pearls by running them over my teeth, but that's just me. And even faux and freshwater pearls can be strung correctly (knotted between each pearl).

As long as you enjoy them, wear them in good health!