Outer strand is one of the numerous variations of the aggrey beads (Blafo Koli). They are European drawn beads altered by "cooking" for use in special ceremonies. Late1800s/ early1900s.
This practice of cooking is continuously done from circa 1900 to today
Middle strand is native powder glass with inlaid glass fragments (Koli Sumue).
Inner strand and the bead cross section view are European translucent dark blue beads faceted by the natives by lapidary work (Akle Koli).