THE US DIME
The word "dime" is an anglicized version of the French word "disme" (pronounced "deem"), meaning tenth.
Dimes are made out of an alloy (a mixture of metals) of 91.67 percent copper and 8.33 percent nickel (before 1965, the dime was made out of silver). The dime has a edge with 118 ridges. This coin is 17.91 mm in diameter and is 1.35 mm thick - it is the smallest, thinnest and lightest US coin.
The dime has been minted in the US since 1796. Although in 1792 a "disme" was minted (one-tenth the silver weight and value of a dollar) but was never put into circulation. The current dime is the Roosevelt dime and has been minted since 1946, when it replaced the Liberty Head dime.
Major sources:
http://en.wikipedia.org/wiki/US_dime
http://en.wikipedia.org/wiki/US_Quarter