Unless, being light for that many beads and all appearing rather smooth and uniform they might be those moulded plastic oblates made to resemble amber?
There is a tendency for plastic to accumulate fine greasy dirt that would need scrubbing to remove.
I agree with Jamey they are likely to be second half 20th century.
Can you please describe the holes' sizes and smoothness and do they have a black deposit on the inside?

Stefany