1 Crown - Elizabeth II D-Day Anniversary, Gold

Tristan da Cunha, a British Overseas Territory in the South Atlantic with a permanent population under 300, issues commemorative coins as a revenue mechanism rather than for any practical circulation purpose. The island has no economy that would support coin use at this scale. These pieces are struck by the Pobjoy Mint on contract and sold directly to collectors, never touching the archipelago they nominally represent.

At .375 fineness — 9 carat — this sits at the lowest threshold conventionally marketed as gold.