Unique Boho Glass Blue Necklace - One of a Kind

Boho Glass Blue Necklace This is a unique necklace that's made of glass with a material inside that's a deep cobalt blue. It beautiful and retro! It measures approx 9 inches and has a solid clasp. The pendant hangs on a rope material. I don't know what is in the center. I tried to research it but couldn't figure it out.