if there are knots in between the pearls they are most likely freshwater. if they are not uniform in size then they are most likely freshwater... if they are perfectly round and heavy, they may be "simulated pearls" which doesnt mean faux pearls it means simulated - grown in oysters until they are a specific size. means completely fake - glass or plastic or resin.... so there are 3 types of pearls - Freshwater, Simulated and Faux - What are these?