Parchment is a centuries-old writing material made from leather, usually calf, goat, or sheep skin. Creating parchment is labor-intensive—first the skin is removed from the animal and any hair or flesh removed, then it is stretched on a wooden frame. The parchment maker or parchminer alternates scraping the surface of the skin with a curved knife and wetting and drying the skin to keep it tightly stretched. This process is repeated to reduce the leather to a thin, taught surface, and finally rubbed with pumice, then chalk to make the surface receptive to ink.
Parchment is more durable than paper, and was often used for religious texts, public laws, indentures, and land records. The five pages of the U.S. Constitution as well as the Declaration of Independence, the Bill of Rights, and the Articles of Confederation are written on parchment.
Reed Enger, "Parchment, Writing on leather lasts longer than paper," in Obelisk Art History, Published April 01, 2019; last modified July 20, 2019, http://arthistoryproject.com/mediums/parchment/.