Ancient Mesopotamia traded with many different regions, exporting different types of goods, and sets of standard weight became essential tools in conducting businesses. The weights themselves were usually made of a very hard stone like hematite or alabaster, as seen on this fine example. Weights modelled in the shape of ducks, with their heads resting along the back, were extremely popular.
To discover more about these ancient peoples, please visit our relevant post: Civilisations of the Ancient Near East.