Think it's three actually. I see three different pendants (the green circular bits, the other circular pendant near her breastbone and then if you look closely you can see a drop pendant too), that's for sure. In fact I see something that could even be a fourth (up near her collar bone).
Your best bet might be asking the magazine (not the one you found the picture in but the one she originally posed for) because they might've actually given them to her for the photoshoot or otherwise know where they're from.
How you find out which magazine that is, however, I don't know. Maybe the editors of this one will tell you? No harm in asking I suppose.
Anyway, welcome to KKW. By the sounds of it you'll fit in nicely.