Hi Jody,
you see, there is every reason that you do the job for yourself once you have practised a bit... and you can take away the pearls without luster, and the ones too small (it takes a better command of knotting to get the knots really tiny next to a tiny pearl), I thought for myself that they are imitation but it is not easy to tell from pictures only. Have you compared the weight to some 2 or 3 combined strands? If glass, they should be really heavy and the tooth test might help too... what did they say at the jewellers shop?