This type of beads have always intrigued me.
They are fairly rare. I found the few we have in the Ivory Coast, occasionally mixed on strands of early generation "Rattle snake" like the ones shown by Beadist. One of them is hourglass shaped.
Some do have a grayish or beige core, some don't (but they may all have a core not always seen and covered up like Bodom beads). It would be interesting to see a broken one to learn more, anybody?
They are probably originating from the Krobo in Ghana and possibly related to some type of Bodom.
JP