Why do 90% “junk silver” coins have a silver content of only 71%?

Steve W.writes: I have been unable to locate any information on why 90% “junk silver” coins have an actual silver content of approximately 71%. Can you enlighten me? Thanks. Steve

Good question – one a lot of people have been asking lately.

U.S. 90% silver coins are commonly sold in bags of $1000 face value. $1000 face value in brand-new (unworn) coins will contain 723 ounces of pure silver. Because of wear, the value of bags of circulated coins are figured at slightly less – 715 ounces. Accordingly, each $1 in face value of U.S. 90% silver is considered to contain .715 oz of pure silver.

Here’s the math: The gross weight of $1 in U.S. 90% minor silver coins is 25 grams. (12.5 grams in a half dollar, 6.25 grams in a quarter, etc.). 90% of that weight is pure silver: 90% x 25 = 22.5 grams. 22.5 grams = .7234 oz.