Iron

## Iron Iron

**Iron** (Lat. *ferrum*; alchemical symbol ♂) is the metal of Mars, associated with masculinity, war, strength, and the color red. In alchemical matter theory, iron was understood as a metal dominated by impure, combustible Sulphur, which gave it its hardness, its tendency to rust (forming red iron oxide), and its magnetic properties. The *Turba Philosophorum* and other medieval texts describe iron as a "sick" metal, suffering from an excess of the fiery principle that makes it brittle when heated to redness and prone to corrosion. Yet iron's strength and its essential role in tools and weapons gave it practical importance that transcended its theoretical imperfection.

The magnetic properties of iron and lodestone (magnetite, Fe₃O₄) fascinated alchemists and natural philosophers, who saw in magnetism evidence of occult sympathies and attractive forces operating in nature. The *Epistola de Magnete* attributed to Peter Peregrinus (1269) and William Gilbert's *De Magnete* (1600) explored magnetic phenomena systematically, influencing alchemical speculations about attractive and repulsive forces between substances. Some alchemists, including Paracelsus, attributed therapeutic properties to iron and its preparations, using iron filings, iron sulfate (green vitriol), and calcined iron oxide in medicines. The "crocus of Mars" (iron oxide, particularly the red form) was used both as a pigment and as a medicinal preparation, believed to strengthen the blood and restore vitality.

The smelting and working of iron required higher temperatures than other common metals, making it a test of the alchemist's mastery over fire. The transformation of iron ore into metallic iron through reduction with charcoal was understood as a kind of resurrection, liberating the metal from its stony prison. The hardening of iron through quenching (rapid cooling) and the softening through annealing (slow cooling) demonstrated that metals could be altered in their properties through heat treatment, supporting alchemical theories about the malleability of metallic natures. Modern chemistry recognizes iron (Fe, atomic number 26) as the most abundant element on Earth by mass and understands its magnetic properties as resulting from the alignment of electron spins in its crystal structure. The symbolic dimension of iron—representing martial strength, the masculine principle, the power to cut and separate—made it important in alchemical allegory, where the "sword of Mars" or the "chalybs" (steel) represented the discriminating power of the intellect and the force necessary to overcome resistance in the work of transformation.

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