I showed the short strand of beads to a seller of old Bakelite and she thinks they are polyester. Polyester is listed as one of the many plastics used to imitate amber on several web sites. I am going to have one of them tested at the plastics test laboratory I used to identify the HIPS bead.

The beads smell like polystyrene when hot-needled, but the info about amber imitations says that polyester will have the same odor as polystyrene when burned. That is interesting to me - possibly these plastics are mixes or co-polymers.

Will let you know the outcome of further tests!