went on a Google image search and found this lovely site along the way...borrowed this image to show -

http://www.jewelsdujour.com/2013/11/the-intricate-art-of-micro-mosaics/

There are dealers, auctions and auction houses listed on the above site that could prove helpful in the long run, I haven't even explored it yet.

I searched Google images for

jewelry using ancient mosaic glass fragments

While it may not produce answers, it's still a fun ride -