1 Dollar Hadrian gold coin

Palau's micro-gold program, which produced dozens of miniature .999 fine pieces in the 2000s and 2010s, was largely driven by the secondary collector market rather than any domestic monetary need — the Republic of Palau has used the US dollar since independence and has no central bank issuing circulating coinage. These pieces were contracted through European minting intermediaries and sold directly to numismatic distributors.

Hadrian's reign saw one of antiquity's most ambitious coin-portrait programs, with die engravers producing unusually individualized likenesses across multiple denominations. At 0.5 grams, the entire gold content of this piece would have been worth a fraction of a single Roman aureus.