Amulet

object that is typically worn on one's person, and is alleged to have the magical power to protect its holder

An amulet (from Latin amuletum, meaning "charm"), is an object that people think will bring good luck and or protection to its owner.

A scarab beetle amulet from Ancient Egypt.

Usually amulets are gems, statues, coins, drawings, pendants, rings, plants, animals, etc. Even words can be amulets, such as vade retro satana—(Latin, "go back, Satan"), to make bad luck go away.