Fanqui-town’s most commonly used coin was the one that had the widest currency in the world: it was the Spanish silver dollar, also called the ‘piece of eight’ because it was valued at eight reals. The dollar contained a little less than an ounce of fine silver and was embossed with the heads and arms of recent Spanish sovereigns. But among the pieces of eight that circulated in Canton, very few retained the designs that had been stamped on them at the time of their minting. In China, while passing from hand to hand, every coin was marked with the seals of its successive owners. This practice was considered a surety for buyers as well as sellers, for anyone who complained of a bad coin could be sure of having it replaced so long as it could be shown to be marked with the seal of its last owner.
When space ran short, more was created by flattening the coin with a hammer. In due time, the cracked and battered coins would be broken into bits, to be kept in bags and placed upon the scales when a transaction required silver of a certain weight. As coins aged, they became more and more difficult to pass off, even when their content of silver remained unchanged; new coins, on the other hand, were called ‘first-chop dollars’ and were so prized they were valued above their weight. – Amitav Ghosh, River of Smoke (2011)