They could be imitation or they could be dyed cultured freshwater pearls from China (most likely)
Rub two together (gently)-- does it feel gritty, or do they glide smoothly?
Gritty = real cultured pearls; smooth = fake.
They look like dyed, button shaped, freshwater pearls from China. This shape was common about 20 years ago before the Chinese started putting round beads in the center to make them round. So they are 100% pearl nacre. These are the sort of pearls I would find at bead stores. Inexpensive, but lustrous and fun, and real pearls.