I'm getting a different picture now. The larger round pearls seem to also be akoyas, but not the same strand as the baroque akoyas. The overtones, luster and shapes are not the same.
It looks like the previous owner arranged the large pearls next to the clasp so that the very decorative clasp could be worn in front which I can totally understand, given how pretty it is. As for the metal, 585 is 14K gold. I thought it was silver, with patina in recessed areas, but now I see from the back view that those are cut out areas, not areas with patina.