The United States Mint establishes pricing on numismatic gold coins via its pricing grid, and updates were published July 1 in the Federal Register.
The LBMA closing spot price of gold per troy ounce June 30 was $3,287.45. If the average spot price were to remain at that level until the week of sales opening, the pricing grid predicts that the Mint would set the opening sale price at $2,150 for the Sacagawea 25th Anniversary half-ounce gold dollar and at $2,650 for the Superman half-ounce gold $50 coin.
Source – Coin World
LBMA – London Bullion Market Association is a whole sale market for trading precious metals. Gold, silver, platinum, and palladium.