elements
Iron
Fe
- Also known as
- ferrumtelluric iron
- Crystal system
- cubic
- Hardness
- 4–5 on the Mohs scale
- Lustre
- metallic
- Colour
- Metallic grey, rusting orange-brown
- Where it forms
- Native iron is genuinely rare on earth because iron reacts with oxygen and water. Almost all of it is either meteoric or from the very unusual basalts of Disko Island in Greenland.
- Chiefly from
- Disko Island, Greenlandmeteorites
Why it is that colour
Metallic. Rust is hydrated iron oxide, and the reason iron corrodes so readily is that the oxide flakes away rather than forming a protective layer, exposing fresh metal.
Safety
Metallic iron is safe. Iron overload is a real medical condition — haemochromatosis — and iron supplements are a leading cause of poisoning in young children, which is a reason iron tablets are child-resistant.
Where it comes from
Iron ore is mined in enormous quantity, chiefly in Australia and Brazil, but from oxides rather than native metal. Native iron is a specimen curiosity.
Historical use
The Iron Age is named for it because iron working, unlike bronze, requires no scarce imported tin — iron ore is everywhere. That made metal tools available to ordinary people and changed agriculture and warfare together.
Recorded as history and attributed where possible. That a stone was used for something establishes that people used it, not that it worked.
What is attributed to it, and since when
Mars in the alchemical scheme, and associated with war, blood and protection across an unusually wide range of traditions. Iron as a defence against fairies, spirits and the evil eye is documented across Europe, the Near East and South Asia — horseshoes over doors, iron nails in cradles, iron in the pocket. That belief is old and widespread.
Described, not endorsed. Dating a claim is not the same as assessing it — but an association that first appears in a book published in 1985 is not an ancient inheritance, whatever the label says. A sincere account of feeling better is compatible with the stone doing nothing — see the placebo effect.
Worth knowing
The near-absence of native iron on earth is why meteoric iron mattered so much. Before smelting, the only metallic iron available anywhere came out of the sky, and the ancient Egyptian word for it translates as something close to "iron from the sky". The dagger buried with Tutankhamun is meteoric, confirmed by analysis in 2016: its nickel and cobalt ratios match iron meteorites and not any terrestrial source.
The folklore about iron and fairies is one of the more geographically widespread beliefs there is, and it has an appealing if unprovable explanation: iron working arrived and displaced an older world, and the older world's inhabitants were remembered as being driven off by the new metal.
Identity checked against IMA-CNMNC master list, June 2025.