Have seen and handled them, but don't own any. The ones I am thinking of are not broken beads but flat pieces, very ornate, will try again to locate some image/images. (Not the inexpensive re-ground irridescent monochrome shards that hit the market 5 or so years ago.)

https://www.pinterest.com/glassmurrine/ancient-mosaic-glass/

Came across an image of a brooch from a shard said to have been Ptolemaic, made in Cairo...