Half dollar coins are a popular collectible item for coin enthusiasts. The half dollar coin is the largest coin in the United States and is twice the size of a quarter. The half dollar coin is 30.61 millimeters in diameter and 2.15 millimeters thick. It weighs 11.34 grams and is composed of 91.67% copper and 8.33% nickel.The half dollar coin is larger than the quarter, dime, and nickel coins. The quarter is 24.26 millimeters in diameter and 1.75 millimeters thick. It weighs 5.67 grams and is composed of 91.67% copper and 8.33% nickel. The dime is 17.91 millimeters in diameter and 1.35 millimeters thick. It weighs 2.268 grams and is composed of 91.67% copper and 8.33% nickel. The nickel is 21.21 millimeters in diameter and 1.95 millimeters thick. It weighs 5 grams and is composed of 75% copper and 25% nickel.The half dollar coin is a popular collectible item due to its size and composition. It is also a great way to add value to any coin collection. Whether you are a beginner or an experienced collector, the half dollar coin is a great addition to any collection.