The United States issued gold certificates, the face value of which was identical to their face value in dollars, from 1879 to 1934, when the country abandoned the gold standard.
Gross Processing Margin (GPM) is the difference between the cost of a commodity and the revenue generated after the commodity has been sold as a finished product.
In the financial arena, the term hardening is commonly used to refer to a period of rising prices and decreasing volatility, especially in commodity trading.
Hotelling theory determines the price or yield at which the owner of a non-renewable resource will extract it and sell it, rather than leave it and wait.