An anchoring element of a tracking device comprising an electronic tag with a unique identification, an embedding method, and a tracking method of a metal precious object provided with such tracking devices are disclosed. The method comprises the steps of embedding said electronic tag with a unique identification in a ceramic case, embedding said ceramic case in an anchoring element in the shape of a metal frame with open faces, joining said anchoring element to a portion of said metal precious object by laser micro welding, wherein said step of embedding said ceramic case provides to defining at least a recess for each side of said metal frame, locating said case inside the perimeter of said metal frame through said through-slit and blocking it there by means of local melting of material of the same nature of said metal frame so as to obstruct an opening of said through-slit.