The Egyptian Ankh symbol is also known as the key of life. The middle piece is the ancient symbol of the Aten-the Sun Sphere - the source of all life which became the only symbol of religious significance during Amenhotep IV, who later took the name Akhenaten in worship and recognition of Aten. In his poem "Great Hymn to the Aten", Akhenaten praises Aten as the creator, and giver of life.
The sun wheel in the necklace appears in the form of the seed of life which is the geometric pattern of creation itself.