This is the Hexafoil Pendant (Closed), showing the base symbol from which this and similar pendants are derived in my collection.
I stumbled upon the symbol in my own spiritual contemplation.
It is a sacred symbol to me because it symbolizes the continuous flow of the energies of life, love and healing.
I have visualized the symbol over sites of pain, like a headache, for example, and found that it can work,
especially if one incorporates pale green or green and white purifying energies into visualization.
The symbol is derived from the Flower of Life and the Seed of life therein, also scaling to incorporate itself in the Fruit of Life.
It has always helped to bring relief to me. I hope it can help you, too.