goldbeater's skin

From the use of cow intestines as a separator in the manufacture of gold leaf.

goldbeater's skin (countable and uncountable, plural goldbeater's skins)

1. The outer membrane of cattle caecum.
   • 1997, Janet Farrell Brodie, Contraception and Abortion in Nineteenth-century America, →ISBN, page 208:

     The Comstock laws that forbade the importation of contraceptives were never enforced against goldbeater's skins or their molds, so that throughout the decades when the laws against reproductive control were most stringently enforced a constant supply of materials ready to be turned into condoms was available.

   • 2015, Ed Regis, Monsters: The Hindenburg Disaster and the Birth of Pathological Technology, →ISBN:

     The membrane had been used, perhaps since antiquity, to make gold leaf, which goldbeaters produced by starting out with a small ingot of gold and beating it thinner, then sandwiching the leaves between sheets of cow intestines, ultimately creating a stack of alternating goldbeater's skins and gold leaf that could be more than 100 layers deep.

   • 2018, Robyn Bennis, By Fire Above: A Signal Airship Novel, →ISBN, page 34:

     Even when trains came in with fresh girders, luftgas, or goldbeater's skin, the quartermaster would only let a little out at a time, and kept the balance in the warehouse.