Issues about the manufacture of Byzantine mosaics and the implications of these in wider terms relating to social and economic questions about the art form have been little discussed. This paper brings together evidence about Byzantine glass mosaic tesserae gathered from archaeology, glass technology and glass analysis, and synthesizes these into a discussion of three aspects: distribution; manufacture; trade and price. It looks to examine how these different elements can be used to form a more detailed composite picture about the production and distribution of Byzantine mosaics. It also proposes ways in which glass analysis can be used in a more coherent way to extend our understanding of mosaic glass production.