In medieval alchemy, each of the magic squares, and therefore each of the corresponding planets, was associated with a particular metal. The essential pursuit of alchemy was not merely the transformation of base metal into gold (although it is often portrayed as such), but rather the larger and more noble aim of transcending the mundane to achieve the spiritual. In each of these magic squares and its associated metal was seen a relationship between the soul and spirit and the body. Saturn’s metal was lead, which represented the body concealing the light of the soul. We now know that lead does indeed  provide a shield against many types of radiation, a fact which medieval alchemists appear to have known intuitively. Jupiter’s metal was tin, which represented the soul emerging from the constraints of the body. Tin ore is dark and indistinct in rock, but, when heated, it flows silver-white. The metal corresponding to the Square of Mars is, naturally, iron. It was held to represent the dominance of the body over the spirit. The Sun’s metal is hold, which represents the spiritual truth which lies at the heart of the universe. The metal of Venus is copper, the metal of mirrors, and it represents the very opposite of iron, namely the dominance of spirit over the body. Mercury’s metal, quicksilver, was considered representative of the perfect balance of spirit and body, and the Moon’s silver was the presentation of the soul as the perfect reflection of the spirit.