This tumbler is finished with a Japanese glaze called Shino. This is a carbon trap glaze, meaning the surface or glass traps the carbon rich environment of the kiln, giving it the variety of green colors. This piece also has wood ash that is placed on the tumbler as it is loaded into the kiln. This piece was fired for a total of 40 hours in a gas kiln. It is signed with 22k gold leaf on the bottom.