Actually, ancient glass, having been rather neglected by archaeology for decades, is a pretty exciting topic in scholarship right now. The main thing is that glass persists–it’s very stable. After fabric rots and metal turns to a scrap of rust, there will lie a necklace, still scattered across a chest that itself has turned mostly to earth.
Bead typologies, for example (that is, the classification of different styles/shapes/decorative motifs/colors) can allow scholars to trace trade routes, as they study the distributions of different bead types over time and geography. Glass production is kinda industrial in nature, not like spinning or beer that make good cottage industries. It was often produced in one place, and then sold on to artisans elsewhere, and then the beads themselves were traded across entire continents.
Chemical analysis of the glass can do even more to trace routes, since different compositions and incidence of different mineral contaminants can allow archaeologists to trace glass production to individual sites, thousands of years after the fact. It’s dizzying, really.
The downside is that for a long time, archaeologists regarded beads as unimportant trinkets, and antiquities dealers understood that they were easy to take and easy to move. So an awful lot of the most exceptional beads we have from the distant past spent time in private collections or uncategorized drawers somewhere in a museum back room, so they’ve lost much of what we could have learned from their original provenance. Maybe we’ll be able to turn new analytical tools on some of these to reconstruct more of their past.
