Now, I could be wrong because it's hard to diagnose the pearls from a photo, but they look exactly like my Grandmother's Richelieu faux pearls.
I'm basing that off the the way they are strung. The way the stringing thread is attached to the clasp. The look of the clasp. And the look of the pearls themselves. My Grandmother's faux pearls have a clasp that is marked Sterling Silver. The pearls are very ivory in color with no overtones. They are also have a very consistent surface with no obvious flaws.
That said, for old faux pearls, they look great when I wear them. My Grandmother gave them to me when I was 11 because she knew I loved pearls. She told me, "They were Richelieu, which is the best pearl that is not a pearl." My heart sank. I didn't wear them for 40 years. A few years ago, I dug them out, cleaned them up, restrung them, and they look dynamite on.