BLUE STONE/GLASS NECKLACE, beautiful, layer it?

I THINK this is stone... I know that is odd, but I can't tell! It is really beautiful, and the small beads are definitely stone... none of the blue pieces are the same, I THINK they are hand faceted stone...? Anyone? Feel free to weigh in. L: 16", each stone is roughly 7/8 x 1 5/8" Would also be great layered with other necklaces... Thanks for shopping with us and feel free to ask me any questions!!!