Sets of standard balance weights were used to weigh goods in the Byzantine world precisely. Weights produced during the Byzantine Era were made of gold, silver, bronze, lead, glass, and stone. Throughout the Middle Ages, bronze (an alloy of copper and tin) was rarely used, as the Byzantine Empire had lost most of its tin-producing provinces in the west during the fourth century AD. It has been suggested that disc weights gradually took over sphere weights until at least the early 9th century and possibly the 12th.
To disocver more about Byzantine art, please visit our relevant blog post: The Byzantine Empire, Art and Christianity.