From the 6th century BCE onwards, the earliest coins of India, called punch-marked coins, were mainly made of:

The punch-marked coins, the earliest coins of India, were mainly made of silver, and some were made of copper.

About punch-marked coins:

• They were first used from about the 6th century BCE, at the time of the Mahajanapadas.
• They are called "punch-marked" because symbols were punched (stamped) onto them using separate punches or dies.
• They were usually rectangular or square, and sometimes round, pieces of metal, cut to a standard weight.
• They had symbols such as the sun, a wheel, animals (elephant, bull, dog), trees, hills (arched hills) and geometric designs.
• They did not have the names or portraits of kings.
• They are known as "karshapana" or "pana" in ancient texts.

NCERT on punch-marked coins:

• NCERT notes that the earliest coins, which were in use for about 500 years, were punch-marked coins.
• They have been found in large numbers across the subcontinent.
• They were issued by kings and possibly also by merchants, bankers and town communities.
• They show the growth of trade and urban centres during the second urbanisation.

Later coins in India:

• Indo-Greek kings issued the first coins with the names and portraits of kings.
• The Kushanas issued gold coins on a large scale.
• The Satavahanas issued coins of lead and potin.

Coins and the economy:

• The use of coins made trade easier than barter.
• Coin hoards found by archaeologists show trade routes and economic activity.

Why not the other options?

• ✗Gold coins became common later, under the Kushanas and Guptas.
• ✗Iron and bronze were not used for punch-marked coins.