Thank you for responding Floor.
Yes, the lantern shaped beads are indeed a hard plastic. When looked at under a loupe (located under the sofa this am) they have crazing on the surface. I don't see evidence of a seam anywhere. Might they have been machined?
With regard to the facetting, I meant to say that the facets looked ground not molded - as they are indeed inconsistent shape wise - but quite clean and sharp. Thank you for clarifying the process.