es: SELLO AL CUÑO
Seal in the past was used for registering property, letters, etc. Hot wax was put over the small space where the two parts of paper join and stamped with the owner’s trademark; this sealed the letter and proved it had not been opened.
A seal is now used by potters as a trademark. It can be made in clay or any other material, have any shape, round, square, etc. and should be long enough to hold comfortably. At one end the trademark is modeled in relief or recessed and if made in clay it should be fired. This method is only needed if you want a special design, such as your initials. If not, you can find a small object with a shape you like and indent it into the clay.