Article 1, Sec. 8, ONLY Congress has the power to make coin and determine it's value.

Article I, Sec. 10, Clause 1 states that NO state shall make anything but gold and silver coin a tender in payment of debts.

10th Amendment states that the powers not delegated to the United States by the Constitution, nor prohibited by it to the States, are reserved to the States respectively, or to the people.

The Coinage Act of 1792 ties the value of the dollar to gold and silver.

Eagles—each to be of the value of ten dollars or units, and to contain two hundred fort-seven grains and four eighths of a grain of pure, or two hundred and seventy grains of standard gold..

Quarter Eagles—each to be of the value of two dollars and a half dollar, and to contain sixty one grains and seven eights of a grain of pure, or sixty seven grains and four eights of a grain of standard gold.

Dollars or the same is now current, and to contain three hundred and seventy-one grains and four sixteenth parts of a grain of pure, or four hundred and sixteen grains of standard silver,

Half Dollars—each to be of half the value of the dollar or unit, and to contain one hundred and eighty-five grains and ten sixteenth parts of a grain of pure, or two hundred and eights of a grain of standard silver.

Quarter Dollars—each to be of one fourth the value of the dollar or unit, and to contain ninety-two grains and thirteen sixteenth parts of a grain of pure, or one hundred and four grains of standard silver.

Dismes—each to be of the value of one tenth of a dollar or unit, and to contain thirty seven grains and two sixteenth parts of a grain of pure, or forty one grains and three fifth parts of a grain of standard silver.

Half Dismes—each to be of the value of one twentieth of a dollar, and to contain eighteen grains and nine sixteenth parts of a grain of pure, or twenty grains and four fifth parts of a grain of standard silver.

Cents—each to be of the value of the one hundredth part of a dollar, and to contain eleven penny-weights of copper. Half Cents—each to be of the value of half a cent, and to contain five penny-weights and half a penny-weight of copper.

Federal Reserve Notes are unconstitutional as they are fiat money and bills of credit.