Several groups of beads are shown here - all are polystyrene - and some were sold as Bakelite. Some really do a good job of looking like old Bakelite.

The hot needle test is a quick way to test for polystyrene. Heat the needle an press the end lightly into the inside surface of the hole. If the needle sinks in, you can be sure it's not Bakelite. If you need to learn what polystyrene smells like - get a plastic container with a PS - 6 recycle mark and hot needle it. Be careful and don't inhale a lot - and you won't have to.

Some other amber imitations are apparently made from a variety of materials like polyester, epoxy, nylons, and PVC (polyvinyl chloride) resins. I've not encountered them as I'm focusing for the time being on beads trade into Africa. However it's a fascinating topic!