The gesture also became a popular salute in heavy metal, and gained Satanic associations.
In Middle Eastern cultures, a similar hand protection symbol is the Hamsa (خمسة) also known as the Hand of Fatima, the Hand of Miriam, or the Hand of Mary, in Muslim, Jewish and Christian traditions. It's an open right hand with the palm facing forward, sometimes with an eye in the center.
The Hamsa is thought to predate all of these three religions and to have originated in ancient Mesopotamia. In Islam, the number five has added significance, and the five fingers may represent Mohammed and his household members, or the five pillars of Islam. Stylized versions are popular in design and jewelry. Traditionally, silver might used for the amulet, with its associations of purity.
So, if you're looking to hedge your bets about the Evil Eye and perhaps add some luck, a beautiful Hamsa charm might be the perfect thing to shop for...