Help with any Pearl info you can provide!

by Sonia
(Phx,Az)

I received these pearls as a gift about 30 years ago, and I know nothing about them, and cannot find anything on the net. I was told they belonged to his mother or grandmother, and they received them as a gift. They are 18inches, and perfectly shaped, and the luster is amazing. The clasp is marked only sterling. About 20 years ago, I was told they are Acoyas (sp),but was not to interested to follow up. they are in the original soft, quilted tri-fold case. Any help, or guidance where I can find more would be appreciated.