These aren't terribly old beads (1960s - 70s?) but I picked up the necklace at Todd's Farm, an outdoor antique flea market in Rowley, MA. I had never seen such small examples of pottery beads from Peru. The small beads are 5-6 mm diameter.

Also, the central pendant is an open pitcher, which is sweet.

The tubular black space-filling beads are rather rough at the edges and uncomfortable to wear, so I think I'll re-do this necklace with some small black seed beads as replacements.