Well, it's anybody's guess; they were excavated near Bamako, Mali in 1963, which was a primary stopping place for caravans going east and west.
My guess is late Islamic. Beads like this don't turn up too often, and when they do, they occur in groups of one, combined typically with a few dozen or hundred other beads, all of which vary. The wearers liked to combine beads, the wilder combination, the better.
These can be made into a beautiful necklace by stringing or by wire-building. Just ask, and I'll tell you how to do it or who will do it for you.
antiquity25