Of interest to this thread:

"The Constitution ‘was designed to provide the same currency, having a uniform legal value in all the States.’ It was for that reason that the power to regulate the value of money was conferred upon the Federal government, while the same power, as well as the power to emit bills of credit, was withdrawn from the States.
The States cannot declare what shall be money, or regulate its value. Whatever power there is over the currency is vested in the Congress." Congress provided in 31 U.S.C.A. section 463