Freshwater or Tahitian Cultured Pearls?

by Janet Boyle
(Charlotte, NC)

I bought a strand of cultured black pearls at a charity auction, the appraisal shows their appraised value at $4,750 with pearls between 10mm and 12mm.

They have a beautiful peacock overtone as it says in the appraisal and has surface blemishes here and there.

I take it into a local jeweler and he says they're junk freshwater pearls but the donor says they're cultured pearls not freshwater.

Who do I believe? How can I tell?