The use of seals, in wax, in lacquer or embossed on paper, to authenticate documents, is a practice as old as writing itself. Seals of this nature were applied directly to the face of the document or attached to the document by cords in the owner's, or to a narrow strip of the document sliced and folded down as a tail but not detached from the document. This helped maintain authenticity by not allowing the reuse of the seal.

Signet rings, generally bearing a coat of arms, are made by intaglio engraving, either in metal or gems (generally semiprecious). Agate is a frequent material, especially carnelian or banded agate like sardonyx; the banding make the impression contrast with the ground.