Your necklace is composed from beads valued by the Paiwan of Formosa (Taiwan), and is, then, probably a Paiwan necklace. Are the spacing beads white shell (perhaps tridacna)? These are not typical of Formosan constructions, but are seen among some Philippine beads. How was it (or they) represented to you?

Although the origin and time of these beads remains more-or-less unknown, their reputation suggests that they may have considerable age, Whether they can be regarded as "trade beads" may be a matter of opinion. I would not call them "trade beads."

Paiwan beads are discussed and shown in my article for the proceedings of the Borneo International Beads Conference, published this past October.

You are fortunate to have these specimens. Enjoy them.

Happy 2011. Jamey