Kennedy Half Dollars90% Silver Composition (1964)Designer – Engraver: Gilroy Roberts Metal Composition: 90% Silver – 10% CopperDiameter: 30.6 mm Mass / Weight: 12.5 grams40% Silver Composition (1965-1970)Designer – Engraver: Gilroy Roberts Metal Composition: 40% Silver – 60% CopperDiameter: 30.6 mm Mass / Weight: 11.5 gramsClad Composition (1971-Present)Designer – Engrav ...