in fact the oval opaque beads are red jasper- much harder and denser than bauxite- i had a good look at all of these strands yesterday-

It looks like these are old jasper Lantana beads from the Yoruba living in Nigeria, West Africa.
In the old ones the perforations were pecked, the newer ones like these are just drilled.

Stefany and Hans: I think you both are right! The book "African Beads, Jewels of a Continent" written by Evelyn Simak and Carl Dreibelbis gives an explanation of those beads on page 85. You can see there a picture with jasper beads, locally called lantana. "In the old kingdom of Benin jasper beads were one of the bead types reserved for royalty and a small elite group of family and court members. The wearing of royal beads by ordinary citizins was punishable by death (!). And traditionally the perforations of Lantana beads are not drilled but pecked with a special tool, called esoro. The making of eighteen beads, the number required for a necklace, took up to a week."

By the way: when I was looking for this explanation in the above mentioned book I saw that the copy you can see on my image is indeed a copy directly from this book!
How nice that BCN is there to discuss about these kind of things, to learn and to go for the right answer.