This is a question every new beader asks when they first encounter Venetian Beads. And then they ask, “What size wire should I use?”
Venetian Beads, Murano Beads
The most common size of holes of Murano Glass Beads is approximately 1mm. Approximate because they are most often made on 1mm diameter copper rods, which heats up and naturally expands. The glass wrapped around it expands as well, but when the glass and the copper cool, they both shrink. So we generally have a ~1mm hole and for larger beads, the mandrel will be larger as the mandrel must support the bead in the fire.
Mandrels being prepared to make our large hole beads
So the short answer is that any wire which is less than 1mm can be used for Venetian & Murano Glass Beads. The important issue is the weight of a bead. So larger beads from 16mm up through our large 30 and 40mm beads will need a heaver (larger) gauge wire.
Note: Venetian/Murano Beads will always be slightly abrasive around the edges. This is not a defect, simply how the beads are made.
Bracelets or Necklaces?
Bracelets will require a heavier gauge because bracelets are much more active and get more abuse than a necklace. Necklaces, especially those with Swarovski or small beads can be strung on a smaller gauge because they will not be subjected to as much stress.