The gestation period for an elephant is 640 to 660 days. This is equivalent to about 95 weeks, or 22 months, and is the longest gestation period of any mammal.
Dimes dated after 1964 are copper-nickel clad and contain no silver. Quarters are also clad, except for the bicentennial commemorative coins with an S mint mark that were produced for mint and proof sets. Kennedy half dollars from 1965 to 1970 were 40 percent silver composition. After 1970, all Kennedy halves were clad, except the same S bicentennial issue.
Although it may seem unusual today, the United States government once issued a coin worth less than one cent: the half cent. The copper U.S. half cent was authorized for production on April 2, 1792. During its 64-year lifespan as a circulating denomination, five different basic design types of the tiny (0.93-inch) coin were struck. The coins were struck at the Philadelphia Mint and do not have a Mint mark.