Indeed it is possible. The most common color for the bases of millefiori-decorated beads, made for the West African trade, is typical dark blue glass that appears black. These bases are often not full-fledged beads, but rather tend to be a little twist of glass to give something to apply the beads elements to. This is why they are small, and why they very often can be seen only at one end of the bead.

My reply was solely based on Gabriel's remark that "There is black hole deposit suggesting that the bead is old."

The bead might also just have a dirty perforation.

Unless one can SEE a bead, one must rely on the description offered. I began to change my mind about the bead when I came to realize it is tabular (which I could not tell from the first photos). And the "black deposit" continued to confound me, and incline me toward a non-Venetian origin.

The new scans clarify that the bead is most likely a Venetian trade bead, and closely related to the beads shown by Evelyn from the Picard book. Whewwwww!

Jamey