So... A stone cup version of the flower pot? Unfortunately, we can't change the model shape without mods, so we can only change the texture. If you want something more particular, then you would need to get a picture for us, because flagon is very general and doesn't give us an idea of exactly what you want.
So, I'm going with medieval styled "stone cup", but, what size?
These are all made by me just now, so, if that counts as the "source material".