Geopiece of the Day: The Iron Pillar

Standing at the center of the Quwwatul Mosque the Iron Pillar is one of Delhi's most curious structures. Dating back to 4th century A.D., the pillar bears an inscription which states that it was erected as a flagstaff in honour of the Hindu god, Vishnu, and in the memory of the Gupta King Chandragupta II, whose reign extended into the 4th century A.D. How the pillar moved to its present location is not recorded in history. The most amazing part of the pillar´s story highlights ancient India's achievements in metallurgy. The pillar is made of 98 per cent wrought iron and has stood 1,600 years without heavy rust building up on the structure or decomposing.

The Iron Pillar

The Delhi Iron Pillar is a classical example of massive production of high class iron and is the biggest hand-forged block of iron from antiquity. It is made from wrought iron, which is a process of joining or folding two pieces of metal by heating them to a high temperature. The iron that was used also has a very low content of carbon which was unusual for the time. 

The Pillar stands at 7.3 metres tall, with one metre below the ground; the diameter is 48 centimetres at the foot, tapering to 29 cm at the top, just below the base of the wonderfully crafted capital; it weighs approximately 6.5 tonnes. Do not forget that it is only one piece of iron, folded and welded together to create the massive structure.

It is a demonstration of the high degree of accomplishment in the art of iron making by ancient Indian iron and steel makers. It has been said that the Indians were the only non-European people who manufactured heavy forged pieces of iron and the pieces were of the size that the European smiths did not learn to make more than one thousand years later.