The Wikipedia article of the day for July 23, 2019 is Coinage Act of 1965.
The Coinage Act of 1965 eliminated silver from the United States dime (ten-cent piece) and quarter dollar, and also reduced the silver content of the half dollar from 90 percent to 40 percent. There had been coin shortages beginning in 1959, and the United States Bureau of the Mint expanded production to try to meet demand. Increased industrial demand for silver drove its price higher; there was widespread hoarding of silver coins. With government stocks of the metal being depleted, President Lyndon B. Johnson recommended that Congress allow silverless dimes and quarters, and debased silver half dollars. Congress passed the bill rapidly and Johnson signed it on July 23, 1965. The new coins began to enter circulation in late 1965, and alleviated the shortages. Precious metal coins vanished from circulation beginning in 1967 as the price of silver rose. The act also banned the production of silver dollars until at least 1970.