The pillar does not rust despite being exposed to the elements for over 1,600 years.
Scientific analysis shows the presence of a 'passive' protective layer of misawite (delta-FeOOH), which inhibits further corrosion.
The pillar was moved to the Qutub complex by the Delhi Sultanate rulers in the 13th century.
The shaft has a diameter of 41 centimeters at the base and 29 centimeters at the top.
Metallurgical tests indicate the pillar was forged by hammering individual lumps of hot iron together in a process known as forge welding.
The inscriptions identify 'Chandra' as the monarch, often associated with Chandragupta II.
A deep hole at the top of the pillar suggests it may have once held a decorative Garuda figure.
The Iron Pillar of Delhi is a 7.2-meter-tall, 6-ton wrought iron column dating back to the Gupta Empire, specifically the 4th or 5th century CE. It is world-renowned for its remarkable corrosion resistance, which metallurgists attribute to a high phosphorus content and a protective passive film of iron hydrogen phosphate hydrate. Originally constructed as a standard for a temple dedicated to Vishnu, it was relocated to its current site in the Qutub Complex during the medieval period. The pillar features Sanskrit inscriptions in the Brahmi script that identify a king named Chandra as the patron. It is composed of 98% pure wrought iron with a very low sulfur content, differing significantly from modern steel. The column remains standing in the courtyard of the Quwwat-ul-Islam Mosque, surrounded by the ruins of various historical periods. It is an archaeological anomaly that has challenged scientific understanding of ancient Indian metallurgical techniques for centuries.
From the southwest corner of the mosque courtyard for a framing that captures both the pillar and the surrounding arched colonnades.
Walk around the column to view the various inscriptions and the protective barrier installed to prevent physical contact.
Combine your visit with a broader tour of the Qutub Minar complex to contextualize the historical layers.
Avoid touching the pillar, as the oils from human skin can disrupt the protective surface film.
Do not rely on local legends claiming that standing with your back to the pillar brings good luck, as physical contact is strictly prohibited by security.
Maintain a respectful distance behind the installed railing; do not attempt to climb or touch the monument.
