The evil eye is a superstitious belief in curse, believed to be cast by a malevolent glare, usually given to a person when one is unaware. It dates back at least to Greek classical antiquity, 6th century BC where it appeared on Chalcidian drinking vessels, known as 'eye-cups', as a type of apotropaic magic. Many cultures believe that receiving the evil eye will cause misfortune or injury, while others believe it to be a kind of supernatural force that casts or reflects a malevolent gaze back-upon those who wish harm upon others. Older iterations of the symbol were often made of ceramic or clay, however, following the production of glass beads in the Mediterranean region in approximately 1500 BC, evil eye beads were popularised with the Phoenicians, Persians, Greeks, Romans and Ottomans. Blue was likely used as it was relatively easy to create; however, modern evil eyes can be a range of colors.
The idea expressed by the term causes many different cultures to pursue protective measures against it, with around 40% of the world's population believing in the evil eye.