The iron pillar located inside New Delhi’s Qutb Minar complex has stood the test of time, remaining intact for the past 1,600 years despite being exposed to sun and rain. The pillar, standing at 7.2 meters high and weighing 6 tons, is a marvel of ancient Indian craftsmanship and metallurgy.
Scientists have been puzzled by the durability of the pillar, as structures made of iron typically rust over time when exposed to air or moisture. However, in 2003, experts at the Indian Institute of Technology (IIT) in Kanpur discovered that the pillar was mainly made from wrought iron with high levels of phosphorus and no sulfur or magnesium, thanks to a technique called “forge welding.”
This ancient method of construction, along with the presence of a thin layer of misawite on the surface of the pillar, has contributed to its longevity. Despite its mysterious origins and missing statue of Garuda, the mount of Lord Vishnu, the iron pillar continues to be a source of fascination for archaeologists and scientists. In an effort to preserve the pillar, the Archaeological Survey of India has built a moat around it to minimize human impact and ensure its continued protection.