They appear to be antique pearls using a "925" stamp on one side of clasp & "OW" & a world in packing containers, so 3 packing containers containing each letter & one symbol. just like this graphic I designed. https://emiliecyri349293.elbloglibre.com/28862873/the-single-best-strategy-to-use-for-gold-south-sea-pearl-necklaces