First - thank, Danny, for the detailed reply and I will definitely consider getting a pair of those nippers - they may be useful for any number of household jobs as well!

I toasted a broken piece or and entire unbroken bead over a candle flame with the following results:

1. Nugget - the surface turned black at once, fair amount of smoke, and the smell was definitely burning paraffin smell.

2. Melon - this one was the most interesting. The surface was completely non- burning with no smoke, no blackening, but maybe a very slight burned plastic smell. When I looked at the burned piece under the microscope, it appears that the coating had melted and flowed into a puddle on the area away from the flame. I could scrape the puddle off in small flakes. Since this material melted but did not burn, I suspect a high temperature silicone oil. Wish I was still at work and could use the analytical lab for positive ID. The appearance of the surface that was heated in the flame changed only a little - slightly lighter blue, with some tiny white specs showing.

3. Round - the surface turned black in the flame, with smoke and a paraffin smell.

4. Disk - I had to heat an un-smashed bead since the pieces were too small to get a good result. The surface material melted into tiny droplets and had a slight plastic smell. It did not burn, so behaved like the material on the melon bead.

5. Square - blackened with paraffin odor.

So in summary it appears that two different treatments (at least) were used on these beads - a flammable paraffin and a high temperature thermoplastic resin.