The Iron Pillar near Qutub Minar draws attention of scientists due to its

The Iron Pillar near Qutub Minar, dating back to the Gupta period (c. 350 AD), is globally acclaimed as a 'rustless wonder' [1]. Despite being exposed to the elements for over 1,600 years, it has remained virtually corrosion-free, which has drawn significant scientific attention to its metallurgical composition [3]. Research, including studies by IIT Kanpur, reveals that its rustlessness is due to a high phosphorus content (approx. 1%) and the formation of a protective 'misawite' layer (a thin film of iron, oxygen, and hydrogen) on its surface. This unique chemical composition, combined with ancient forge-welding techniques, creates an invisible shield against atmospheric corrosion. While its antiquity and craftsmanship are notable, it is specifically the pillar's ability to resist rusting in open-air conditions that makes it a subject of scientific study regarding ancient Indian metallurgical prowess [1].

Sources

1. [1] Science-Class VII . NCERT(Revised ed 2025) > Chapter 4: The World of Metals and Non-metals > The wonder of ancient Indian metallurgy! > p. 50
2. [3] https://www.sciencedirect.com/science/article/pii/S2666523923000909