World's most notable amulet: the Udjat Eye or Eye of Horus

Udjat Eye - Horus eye
Originally uploaded by javas roe

The Eye of Horus (Wedjat)[1] (previously Wadjet and the Eye of the Moon; and afterwards as The Eye of Ra)[2] or ("Udjat")[3] is an ancient Egyptian symbol of protection and royal power from deities, in this case from Horus or Ra. The symbol is seen on images of Horus' mother, Isis, and on other deities associated with her, says Wikipedia.

In the Egyptian language, the word for this symbol was "Wedjat".[4][5] It was the eye of one of the earliest of Egyptian deities, Wadjet, who later became associated with Bast, Mut, and Hathor as well. Wedjat was a solar deity and this symbol began as her eye, an all seeing eye. In early artwork, Hathor is also depicted with this eye.[6] Funerary amulets were often made in the shape of the Eye of Horus. The Wedjat or Eye of Horus is "the central element" of seven "gold, faience, carnelian and lapis lazuli" bracelets found on the mummy of Shoshenq II.[7]

The Wedjat "was intended to protect the king [here] in the afterlife"[8] and to ward off evil. Ancient Egyptian and Near Eastern sailors would frequently paint the symbol on the bow of their vessel to ensure safe sea travel.[9]