Pentacle

(http://www.moonlightmysteries.com/statuary/details/pentacle02.jpg)

A pentacle or pantacle (in Thelema) is an amulet used in magical evocation, generally made of parchment, paper or metal (although it can be of other materials), on which the symbol of a spirit or energy being evoked is drawn. It is often worn around the neck, or placed within the triangle of evocation. Protective symbols may also be included (sometimes on the reverse), a common one being the five-point Seal of Solomon, called a pentacle of Solomon or pentangle of Solomon. Many varieties of pentacle can be found in the grimoires of Solomonic magic; they are also used in some neopagan magical traditions, such as Wicca, alongside other magical tools.
(http://en.wikipedia.org/wiki/Pentacle)