Types of Iron in ancient Indian metallurgy

The iron pillar that stands intact in Delhi is one of the many marvels of  ancient metallurgy. Infact, unlike modern metallurgists, 14 different types of iron were known to metallurgists of the subcontinent. According to Rasa Ratna Samuchchaya (dated to the eighth to twelfth century AD), Iron was classified into three basic categories, which are applicable even today –

1. Wrought iron (Kanta Loha)
2. Carbon steel (Tikshna Loha)
3. Cast iron (Munda Loha)

These are further subdivided into-

Kanta Loha

1. Bhramaka kanta loha (Soft magnetic iron)
2. Chumbaka kanta loha (Mild magnetic iron)
3. Karshaka kanta loha (Attracts iron objects)
4. Dravaka kanta loha (Very strong magnetic iron)
5. Ramaka kranta loha (Permanent magnet and very powerful)

Munda Loha

1. Mrudu munda loha (Soft brittle iron)
2. Kunda munda loha (Mottled grey iron)
3. Kadara munda loha (White cast iron)

Teekshna Loha

1. Khara teekshana loha (Brittle but develops good cutting edge)
2. Sara teekshana loha (Fibrous looking softer iron)
3. Hrunnala teekshana loha (Hard and tough fibrous structure)
4. Taravata teekshana loha (Has excellent cutting edge)
5. Vajra teekshana loha (hard and has excellent tampering property)
6. Kala teekshana loha (Develops very hard edge after tampering)

Each of these had their advantages and uses. Modern metallurgists can explore these literature and make use of this knowledge.