Art Deco 30's Venetian Murano Millefiori long barrel shaped beads Necklace.

A very nice addition to my mosaic jewelry collection. This is not called a mosaic but millefiori or Venetian Murano Millefiori Art Glass Bead colored pieces inlaid in glass black beads . Millefiori litteraly, a thousand flowers. A style of ornamented glass made from slices of canes of coloured glass embedded in clear glass, usually like this one in flower like designs
The style was known in Alexandria from the 3rd century BC and in Rome in the first century AD, but is was so called only it was revived and modified at Venice in the 16th Century.
The round little black intermediate beads are not made of glass, nor wood, but a different material? I don't know which one of you might have an idea.