<P> An Eight Royals Coin nominally weighed 550.209 Spanish grains, which is 423.900 troy / avoirdupois grains (0.883125 troy ounces or 27.468 grams), 0.93055 fine, so contained 0.821791 troy ounces (25.561 g) or 394.460 grains fine silver . Its weight and purity varied significantly between mints and over the centuries . In contrast, the Coinage Act of 1792 specified that the U.S. dollar would contain ​ 371 ⁄ grain (24.1 g) pure or 416 grain (27.0 g) standard silver . This specification was based on the average weight of a random selection of worn Spanish dollars which Alexander Hamilton caused to be weighed at the Treasury . </P> <P> The coins had a nominal value of eight reales ("royals"). </P> <P> Before the American Revolution, owing to British mercantilist policies, there was a chronic shortage of British currency in Britain's colonies . Trade was often conducted with Spanish dollars that had been obtained through illicit trade with the West Indies . Spanish coinage was legal tender in the United States until the Coinage Act of 1857 discontinued the practice . The pricing of equities on U.S. stock exchanges in ​ ⁄ - dollar denominations persisted until the New York Stock Exchange converted first to pricing in sixteenths of a dollar on 24 June 1997, and shortly after that, to decimal pricing . </P> <P> Long tied to the lore of piracy, "pieces of eight" were manufactured in the Americas and transported in bulk back to Spain, making them a very tempting target for seagoing pirates . The Manila galleons transported Mexican silver to Manila in the Spanish Philippines, where it would be exchanged for Philippine and Chinese goods, since silver was the only foreign commodity China would accept . In Oriental trade, Spanish dollars were often stamped with Chinese characters known as "chop marks" which indicated that particular coin had been assayed by a well - known merchant and determined to be genuine . The specifications of the Spanish dollar became a standard for trade in the Far East, with later Western powers issuing trade dollars, and colonial currencies such as the Hong Kong dollar, to the same specifications . </P>

What is a piece of eight worth today
find me the text answering this question