When I was shopping the other day I saw 2 little ball vases about 4 - 5" across, and (of course!) could picture roses on them!
They are not porcelain - the material seems to be a sort of stone ware, and was lovely to paint on.
I fired them only to 740 degrees, and took the heat up slowly in the kiln.
This vase has coloured roses on the top, and the bottom half of the vase is covered in irridescent blue lustre. Super!