Articles of jewelry that from antiquity to the Renaissance and later have been considered by the wearers to contribute to the prevention or healing disease, either by reason of an inherent magicalquality of the gemstone or organic substance used or the power of certain magical words inscribed on them. Some such pieces were made with an open back to afford the magical quality closer access tothe wearer's skin. Treatises have been written since 1592 on the powers of such jewelry.
Prophylactic Jewelry

Prophylactic Jewelry
Articles of jewelry that from antiquity to the Renaissance and later have been considered by the wearers to contribute to the prevention or healing disease, either by reason of an inherent magicalquality of the gemstone or organic substance used or the power of certain magical words inscribed on them. Some such pieces were made with an open back to afford the magical quality closer access tothe wearer's skin. Treatises have been written since 1592 on the powers of such jewelry.
References
From: An Illustrated Dictionary of Jewelry, autor: Harold Newman, publishers: Thames and Hudson



