I don't believe you can make a contract payable in gold or silver. Federal Reserve Notes (debt instruments) are legal tender for ALL debts public and private. Says so on your dollar bill.
Yep, the good old Legal Tender Laws of the 1930s. They were challenged in court by people who held valid contracts to be paid in gold or silver coin. The courts held that the Legal Tender Laws were Constitutional, despite the Constitution, in plain words, prohibiting the acceptance of anything but gold and silver coin as money. So those contracts were converted by the courts into contracts for Federal Reserve Notes on a one Federal Reserve Note Dollar per 1/35th ounce of gold equivalency.
The part of the Constitution requiring only gold and silver coin be accepted as money has never been repealed. It's only been ignored by the Supreme Court. No state is permitted under the plain words of our Constitution to acknowledge anything but gold and silver coin as money, and since all transactions in the US take place within one state or another, that should still be binding on every transaction taking place within the United States, but it's been ruled that it's not.
PS The reason those laws made it to the Supreme Court in the first place was that the lower courts consistently (and correctly) ruled that contracts for payment in gold and silver coin were binding, and could not be discharged by payment in Federal Reserve Notes on a 1/35th ounce of gold pe one dollar Federal Reserve Note equivalency. Said rulings were reversed by the Supreme Court.
