10 Dollars - Elizabeth II Single 9 Pond 1898

The "Single 9 Pond" it references is one of the most famous South African rarities — a proof struck in 1898 at the Pretoria Mint, just one year before the outbreak of the Second Boer War ended Kruger's republic entirely. Only a single specimen is confirmed to exist, hence the name, and it last sold at auction in 2010 for over $4 million. This Solomon Islands issue belongs to a well-established category of legal-tender gold miniatures — fractional bullion pieces nominally tied to Pacific island jurisdictions with no meaningful local monetary connection — produced primarily for the collector and novelty bullion market.