Recent excavations in Middle Ganges Valley conducted by archaeologist Rakesh Tewari show iron working in India may have begun as early as 1800 BCE. Archaeological sites in India, such as Malhar, Dadupur, Raja Nala Ka Tila and Lahuradewa in the state of Uttar Pradesh show iron implements in the period between 1800 BCE-1200 BCE. Sahi (1979: 366) concluded that by the early 13th century BCE, iron smelting was definitely practiced on a bigger scale in India, suggesting that the date the technology's early period may well be placed as early as the 16th century BCE.
Some of the early iron objects found in India are dated to 1400 BCE by employing the method of radio carbon dating. Spikes, knives, daggers, arrow-heads, bowls, spoons, saucepans, axes, chisels, tongs, door fittings etc. ranging from 600 BCE—200 BCE have been discovered from several archaeological sites. In Southern India (present day Mysore) iron appeared as early as the 12th or 11th century BCE. These developments were too early for any significant close contact with the northwest of the country.
The earliest available Bronze age swords of copper discovered from the Harappan sites in Pakistan date back to 2300 BCE. Swords have been recovered in archaeological findings throughout the Ganges-Jamuna Doab region of India, consisting of bronze but more commonly copper. Diverse specimens have been discovered in Fatehgarh, where there are several varieties of hilt. These swords have been variously dated to periods between 1700 and 1400 BCE, but were probably used more extensively during the opening centuries of the 1st millennium BCE.
The beginning of the 1st millennium BCE saw extensive developments in iron metallurgy in India. Technological advancement and mastery of iron metallurgy was achieved during this period of peaceful settlements. The years between 322 and 185 BCE saw several advancements being made to the technology involved in metallurgy during the politically stable Maurya period (322—185 BCE). Greek historian Herodotus (431—425 BCE) wrote the first western account of the use of iron in India.
Perhaps as early as 300 BCE—although certainly by 200 CE—high quality steel was being produced in southern India by what Europeans would later call the crucible technique. In this system, high-purity wrought iron, charcoal, and glass were mixed in a crucible and heated until the iron melted and absorbed the carbon. The first crucible steel was the wootz steel that originated in India before the beginning of the common era. Wootz steel was widely exported and traded throughout ancient Europe, China, the Arab world, and became particularly famous in the Middle East, where it became known as Damascus steel. Archaeological evidence suggests that this manufacturing process was already in existence in South India well before the common era.
Zinc mines of Zawar, near Udaipur, Rajasthan, were active during 400 BCE. There are references of medicinal uses of zinc in the Charaka Samhita (300 BCE). The Rasaratna Samuccaya (800 CE) explains the existence of two types of ores for zinc metal, one of which is ideal for metal extraction while the other is used for medicinal purpose. The Periplus Maris Erythraei mentions weapons of Indian iron and steel being exported from India to Greece.