25 Dollars - Charles III U.S. Buffalo gold

Cook Islands has issued legal tender gold under licensing arrangements for decades, with the face value bearing essentially no relationship to bullion content — this $25 denomination contains roughly $70 worth of gold at spot. The format here mimics the American Buffalo series, itself introduced in 2006 as the U.S. Mint's first .9999 fine gold coin, a response to Canadian and Australian competition for the pure-gold bullion market.

At 1.2 grams spread across 58 millimeters, the metal layer is extraordinarily thin — this is a collector novelty, not a bullion vehicle.