3-Strands, ~15" Long; ~0.068" Ivory? Beads: ~800 of 'em!

Aside from their variation in color, these are quite uniform in diameter. The 15 inch length is as they are, rope-twisted; stretched out they may be ~10% longer strings, which would increase the overall bead count.
I haven't tried to examine the thread they're strung on, but the holes in them must be pretty small. What an exercise in tedious labor! The diameter of the visible threaded portion of the barrel clasp is 0.113", for scale.
Does anyone recognize these as far as place of origin...or anything else? Seems to me, on reflection, that a 15 inch choker is pretty small, except perhaps for a child...my neck is ~19". Thanks for lookin'!

 

They don't quite look like ivory, although it's hard to tell with such small bits. Bone would be my guess.

I'm a fairly tall woman, but neck is 13" at the base, so a 15" necklace is quite comfortable on me.

 

I see that twist barrel closure on a lot of vintage Chinese bone carved necklaces ...