From The Art and Popular Culture Encyclopedia
Cornicello, which translates from Italian as "little horn", is an Italian amulet which was worn to protect against the evil eye. Made of gold, silver or red coral, these amulets were said to be sacred to the moon goddess before the rise of Christianity.
Origins and styles
The Cornicello is an Italian-American amulet of Christianity. It is a twisted horn-shaped amulet worn to protect against evil. Cornicelli are usually made out of blood coral or made of gold. The type of horn they are intended to copy is like the twisted horn of an African eland or something similar. Over the years they have become rather stylized and now look less like a natural animal horn than they once did. A regionally popular amulet, they are primarily found in Italy and in America among descendents of Italian immigrants, especially in the Northeast US. You can buy cornicelli at any Italian jewelry store in New York to this day.
These little horns (like the horns of all horned animals) are presumed to have once been sacred to the Old European moon goddess, before the rise of Christianity. Most modern Italians disparage the continued use of cornicelli among Italian Catholics and refer to them as "Satan's horns" or "Lucifer's horns" and silly superstitions.
Related to the corno is the mano cornuta or "horned hand." This is an Italian hand-gesture (or an amulet imitative of the gesture) that can be used to indicate that a man has been cuckolded ("wears the horns") and also to ward off the evil eye. Mano means "hand" and corno means "horn."