The United States Mint states that a dime has a diameter of 17.91 mm (0.705 inches), a thickness of 1.35 mm, and a mass of 2.268 grammes (0.08 ounces). This coin is the thinnest and has the smallest diameter of all U.S. coins.
The composition of dimes is cupronickel, a copper-nickel alloy containing additional elements. Dimes are composed of 8.33 percent nickel, copper, and typically a trace amount of manganese. Cupronickel imparts the silver hue to dimes.
With 118 reeds, the dime’s edge is reeded. These are the sequence of grooved lines that are placed around the edge of dimes to prevent counterfeiting. The original composition of dimes was gold and silver, and individuals attempted to retrieve the precious metals by filing the edges.