Milano Italy Custom jewelry - facetted and cordonato d'oro glass beads

I've found another necklace like this once ago offered on ebay.
The seller said his necklace, has been an original art nouveau piece, but that might have been just to get a better price. I don't know how old it might be.
Beside the facetted rose colored and clear beads with gold inclusions, there is a single metal bead with an impressed maker's mark OP withthe letter M inside the O and Milano written on rhe backside. I first thought this should be from venice/murano, untill i read the brass bead. I haven't found informations about about the maker and period yet, but if so I'll add them.