This is a rolled-pad glass bead, made from a millefiori plaque. As such it cannot be Venetian, because they never made beads this way. Rolled-pad beads date from Roman through Islamic times, and are practically no longer made (even by most fakers--which is how you can tell a bead is a fake).

Your bead is somewhat similar to a bunch Thomas Stricker showed a while back, though from simpler canes. These are Islamic Period beads that inspired certain beads from Mauritania in the Kiffa (muracad) family.

They are fairly rare beads--so enjoy.

Jamey