I am doing a project on Mesopotamia and have stumbled upon their currency system. They have Gerahs, Shekels and Minas. These units of currency are referred to by their laws, yet I can only find pictures of the Shekel on google images. The other coins only come from other civilizations. So my question is did Mesopotamia have physical coins to represent Gerahs and Minas or were they just measure of weight?
If with Mesopotamia you mean the ancient civilisations in Babylonia and Assyria before the Persian conquest (that is: before 535 BC), then we need to say that there were no coins at all. In a Mesopotamian context, a shekel is a unit of weight, not a struck coin. The first coins in the world were minted in Lydia around 600 BC. In Babylonia, coins began to circulate during the Persian (Achaemenid) period.
The only Babylonian coins known and recovered are shekels. The minah was a unit of weight. I have not heard of the gerah being used in a Babylonian context. The Babylonian practice was to put silver pieces in a linen bag and then seal the bag and stamp it with an official weight.