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.
Between 1942 and 1945, the mint stopped using nickel in the Jefferson coins and replaced it with silver. The coins produced were as bright and shiny as silver dimes, quarters and halves! Because these Silver War Nickels were worth more than face value, the Mint put a huge mintmark on each, right above Monticello on the reverse, so they could pull them out of circulation after the war.