Does anyone know what it might have been used for?

Question

During an excavation a co-worker of mine found a 2000 year old Roman artifact. It is a round (ball-shaped), smoothed out, broken stone. Looks like it COULD have been sort of cylinder shaped. There is a man-made hole at the top as if someone pushed a thick nail through from underneath. I thought it might have been a clay water jug, but then I thought the hole on the top might be too small. The hole is about the circumference of a fingernail. Anyone familiar with this? I know its vague and a picture would help, but this is all i can do for now.

Answer 1

A filter or funnel.