Most people would call these marbles - calling them anything else would seem to me to be overly pretentious. I have seen a number of current American production ones. They go for very modest amounts, though sometimes if the glass artist has exceptional skill to put the same amount of detail inside one of these as you see in a large 3 or 4 inch work then those can go for more. I agree with Sue that the ones shown are more along the lines of the mass produced glass bits that are used in the bottom of a vase to hold flowers in place.
I would not call them weights. These are round and would just roll off your paper.