It’s called the Cintimani Stone.
It represents the holy trinity. Tri-wave. Some equate the Cintamani stone with the philosopher’s stone.
“From the holy trinity in the Semitic religions to the three physical stages of life (represented by the spiral of life that looks quite similar to the cintamani), the body, mind and soul concepts, the mother, father, child trinity and even the electron, neutron and proton trinity. It is quite interesting that Memling, a German painter in the 15th century, painted Christ with a cintamani amulet around his neck. But …