Real Pearls or Not?

by Ann Henderson
(UK)

I have a double strand pearl necklace with round pearls it has a lovely 925 silver and mother of pearl clasp. It even has a safety hook I have rubbed the pearls together and they are gritty. Would they be real pearls? On a silver clasp? They came from a deceased estate so i know they are at least 70 years old if not older