These two beads don't look right and may well be fairly recent. For one thing, the middle layer is milky. In the old ones, it is much whiter like the stripes. Also, the hole in the one bead appears to have a rough surface suggesting creation by winding. If the beads were drawn, the surface would be perfectly smooth. Furthermore, the blue glass is too dark. The old beads have much more transparency. The reason for the white layer is so that light passing through the outer layer is reflected off it so the bead looks bright blue. If the glass is too dark, light can't pass through it and the white layer is useless and the glass looks black. If these are wound, they are certainly not Dutch since they just produced drawn beads. Venice might be a source but these are kind of sloppy so I suspect another one... but where?