They appear to be antique pearls using a "925" stamp on a person facet of clasp & "OW" & a globe in containers, so 3 containers that contains each letter & just one symbol. comparable to this graphic I built. https://denispcwu593734.ka-blogs.com/82156854/pacific-pearls-international-s-south-sea-pearl-necklaces-no-further-a-mystery