Monumental architecture required considerable advances in the technology of lifting, loading and transportation of construction materials, building construction ramps, scaffolding, and related tools and implements. As in ancient Egypt or Babylon, appropriate techniques also had to be developed and implemented in India. But more importantly, stone-based construction presupposes the existence of hard metal based tools and implements for cutting and shaping stone. The discovery of iron thus played an essential role in the development of monumental architecture in India which may have in turn given a further impetus to the development of metallurgical skills.

As early as the 4th C. BC, Kautilya's Arthashastra had a section outlining the processes for metal extraction and alloying. Later Sanskrit texts talk about assessing metal purity and describe techniques for achieving metal purity. Various alloying techniques were in use and some may have had their origin in the Harappan or Vedic periods. (For instance, there are references in the Vedic literature that suggest that copper vessels were coated with tin so as to prevent milk from going sour.)

A combination of scholarly investigation and broad dissemination of practical techniques propelled the development of metallurgical skills. The fifth century Iron Pillar of Delhi is a remarkable example of those skills. Standing over 23 feet high it consists of a single piece of iron and has weathered over 1500 monsoons without showing any signs of rust. The pillar is made of wrought iron with an iron content of 99.72 % and appears to have been protected from rust by the application of a thin coating of manganese dioxide.

By the 12th century, construction engineers were using iron girders and beams on a scale unknown in any other part of the world. The most significant use of iron beams was in the temples of Puri and Konarak. The Puri temple contains 239 iron beams and one of the beams in Konarak is 35 feet long. All are 99.64 percent iron and were produced in a similiar manner to the Delhi iron pillar.
During the middle ages, India acquired a reputation for producing very high quality steel and was also able to extract zinc from it's ore by the 14th century. Bidari (an alloy of copper, lead and tin developed in the Deccan) was also extensively used.

Unsurprisingly, developments in metallurgy also had their impact on artillery production. According to A. Rahman (Science in Medieval India), by the 16th century, the heaviest guns in the world were being cast in India and a variety of weapons were being manufactured in the subcontinent. The Jaigarh cannon factory was one of India's best and before the crucial battle of 1857, the Jaipur Rajputs laid claim to owning Asia's largest cannon. Yet, none of the Rajput cannons were ever used to confront the British who succeeded in conquering the sub-continent without ever having to fight against the country's best equipped armies, thus demonstrating that technological progress is not an end in itself.