I think they are likely imitation pearls. Although peach color can be found naturally in freshwater pearls, those are very uniform in color, shape, size, luster etc. and the clasp looks imitation.
However here are a few simple tests we recommend trying:
1.
Rubbing test. Gently rub one of the pearls against another. Real pearl nacre feels gritty while imitation pearls just slide smoothly against one another.
2.
Temperature test. Real pearls are cooler than imitation pearls made of glass or plastic. Do you have any other pearls to compare with, whether pearls you are sure are real or that you are sure are fake? If so, put them in the same ambient temperature for half an hour or so, then touch each briefly to your lips, which are very sensitive to temperature. What do you feel?
3.
Loupe test. When viewed under a 10x magnifier, real pearl nacre appears smooth, while imitation pearls show more texture. This photo by Renee Newman illustrates this-- the top ones are fake.