Dollars weigh one gramme, according to the U.S. Bureau of Engraving and Printing. This is the same for all denominations of U.S. currency.
Since one pound contains 454 grammes, one pound contains 454 bills. In addition, the Bureau adds that these banknotes are sturdy enough to resist 4,000 double folds before tearing and are constructed of 75% cotton and 25% linen. The green ink on banknotes is chemically resistant, and the colour indicates credit that is powerful and stable. In the 1930s, the $100,000 bill used exclusively for Federal Reserve transactions was the highest bill ever printed.