Tin glaze is a type of glaze that can be applied to jugs, statues, large pots, and crafts made of stone or ceramics. It is applied to these items by a glazer at a kiln or magma kiln by using a chunk of cassiterite. Tin bars can't be used for this, so if you want to use tin glaze be sure not to smelt all of your cassiterite into tin.
Tin glaze is worth twice as much as ash glaze, likely partially due to its limited availability. Otherwise, it is functionally identical, making earthenware jugs and large pots waterproof and able to store liquids.
A plate with a tin glaze.