I routinely refer to these as "black chevron beads." Nevertheless, the color of the outer glass is not truly black, because MOST glasses that appear to be "black" are usually a saturated version of a conventional color. [Man, there's a LOT of dialogue about this specific problem/issue here. I really hesitate to bring it up again, lest what I say be misinterpreted yet again....] Among Venetian beads, the most common "black" glass is deep violet. However, since at least the 16th C., Venetians have also made what is called a "madder red," or "wine red," that when saturated passes for black—which is what forms the outer layers of the beads we are discussing.

Rosetta beads with white base layers date from the mid to late 19th C. HOWEVER, we only know this from a few specimens that exist on a few sample cards. These few beads are distinctive. They are small in diameter, and have poorly "whittled" ends. It's not the reasonably precise faceted look of earlier and later (20th C.) beads..., but has the look you'd get if you sharpen a pencil with a knife. Plus, the starry layers also tend to be sloppy.

Moretti introduced the modern chevron beads with white bases, in four-layer and six-layer editions in 1917. All typical late, modern rosetta beads post-date this time (even though they are routinely sold as deriving from an earlier time, and are usually sold as "antique"—which they are not—as I define "antique"). Until some incontrovertible proof comes to light to enlarge our perspective, and push the time of manufacture back—this is what I will maintain.

There are also some (I believe) 20th C. beads that resemble the late 19th C. beads (which should not be surprising at all). These have been presented as the earlier beads, when I believe they are not that.

I have to say I don't know who made the sloppy black five-layer beads we're discussing here, that have a red layer next to a black layer. But I would have to guess that they post-date the introduction of the Moretti beads. And the 1920s seem like a likely time.

As has been pointed out many times here and elsewhere, your millefiori bead has come out of Mali, from Islamic Period digs. It is not a "Roman" bead.

I was just speaking with Andy Hale on the phone about a week ago. I wish he and Kate were still in the beads business—because they always had such great stuff. My collection is richer for it.

Be well. Jamey