A half-dollar coin weighs 11.340 grams, according to the United States Mint. If the coin becomes underweight due to natural wear or through mutilation, the U.S. Philadelphia Mint Center or the Federal Reserve Bank recollects the coin for melting.
Half-dollar coins are made of a nickel-copper alloy, the U.S. Mint states. Only 8.33 percent of the alloy is nickel, with the remaining nearly 91 percent of the alloy consisting of copper and hardening additives. Federal Reserve Banks can only collect coins that have been worn down. If a coin has been adulterated or mutilated, it must be sent directly to the U.S. Mint in Philadelphia.