A brisk trade

The Harappans were busy traders, not only between their own cities, near and far, but also with other civilisations and cultures in and outside India. They exported ornaments, timber, some everyday objects, probably gold and cotton, and possibly some foods.

Their favourite ornaments were beads of carnelian, a reddish semi-precious stone found mostly in Gujarat. Harappan craftspeople worked out special ways to drill them, so a string could pass through, and to decorate them. Harappan carnelian beads have been dug up at Susa in today's Iran, and an ivory comb on the coast of Oman.

They also carved conch shells into beautiful bangles, which needs great skill, since shell is hard.

What they imported in return is less clear. It probably included copper, which was not common in their own land.

The Harappans were masters at working copper, a soft metal. Adding tin to copper makes bronze, which is harder than copper. They used bronze for tools, pots and pans, and some figurines.

For trade they used land routes, rivers, and the sea for faraway places: the first large-scale sea trade in India. Quite a few Harappan settlements lie on the coasts of Gujarat and Sindh. Lothal, a small settlement in Gujarat, has a surprisingly huge basin, 217 metres long and 36 metres wide, a little longer than two football grounds. It must have been a dockyard, a place to receive and send boats carrying goods. A small town's own boats would never need that much water.

Trade on this scale means traders must recognise their goods, and each other! That seems to be the main purpose of the thousands of small seals found at many sites. A seal worked a little like a stamp. They were usually made of steatite, a soft stone hardened by heating, and are only a few centimetres across. Most show an animal, with a few signs above it that belong to a writing system. But nobody has yet been able to read that writing or explain the meaning of the animals. What is certain is that the seals had something to do with trade.