When you learn pottery class from a Japanese woman and your wife loves tea, you will make tea bowls. This is one of my first. It is not perfect. It isn't exactly round, there is no indentation in the foot (very important for something holding hot liquid) and one side is taller than the other. But it turns out, tea bowls aren't supposed to be perfect.
The outside glaze is ancient jasper, inside seaweed, maybe a bit of all temperature black around the rim.