Did God institute a law against the debasing of currency? (RC Sproul)

In "How Should I Think about Money?" Dr RC Sproul states on page 41: >God instituted in the nation of Israel a law against the debasing of currency He further gives the example of coin clipping, which is reducing the actual metal content of a coin, thereby debasing it's actual value. However, he provides no scriptural reference for this statement. The only prohibition that comes to my mind is that condemning dishonest scales, like Proverbs 11:1, among many, but that is very different from debasing a unit of exchange (aka, currency).