Size - looks like an AE3, could be AE4. Would be nice with a ruler next to the coin for scale though.
Weight - Probably one to three grams, wouldn't help too much with ID though, Roman planchets weren't exactly up to modern specifications in accuracy.
Color - is pretty clear to me from the pictures
Metal - is probably copper
The coin looks too worn for me to identify from pictures.
If I had the coin in hand I might be able to get a partial ID, but the legend and exergue seem very worn, and I suspect it would require a great deal of "eye-games" and squinting to get a good sense of either the obverse or reverse legend.
