My humble opinion is Chinese freshwater, quickly drilled and not very expensive. Since China is the biggest producer by far of freshwater pearls... There also seemed to be a time when "natural" shaped (Called "baroque, potato, off-round," etc) cultured freshwater pearls was a big fashion trend (90's-2000's) and I have lots of these in necklaces from China. Non-cultured pearls are actually natural...there are very few of those. Hope that helps.