This is the Eye of Horus, sometimes known as the wedjat eye, used as a popular symbol of protection in Ancient Egypt. The god Horus is represented as a falcon. In Ancient Egyptian mythology, Horus had his eye taken in a fight with his rival Seth, who had killed Horus’ father, Osiris. The eye was later restored by the god Thoth, and became wedjat, meaning whole or healthy.
It became a popular protective symbol, particulary for the dead, and was in popular use for around 3000 years, from the Old Kingdom until the Roman era. It was also used in neighbouring cultures, such as the Canaanite, Syrian and Nubian cultures. Is there anything you keep as a good luck charm or for protection?