An essay by Sumit Guha and Kenneth Pomeranz in the newly published What India and China Once Were: The Pasts That May Shape the Global Future, edited by Sheldon Pollack and Benjamin Elman, reviewed in the Asian Review of Books, discusses Indian exports of cotton. What came back was silver; they quote “an early English visitor”:

India is rich in silver, for all the nations bring coyne and carry away commodities for same; and this coyne is buried in India and goeth out not.

Silver rupee (Akbar)So much silver that in fact

initially India absorbed two to three times as much American silver as Ming China (which until mid 1600s was still importing a great deal of its silver from Japan). The Mughal Empire that emerged in the 1550s was able to switch its currency base from copper and copper-silver alloy to pure silver.