1 Dollar - Elizabeth II 4th Portrait - Treasures of Australia - Opals

The "Treasures of Australia" series, launched by the Royal Australian Mint in the mid-2000s, was built around the country's near-monopoly on global opal supply — Australia produces roughly 95 percent of the world's gem-quality opals, the majority from the South Australian fields at Coober Pedy. This 2008 issue incorporates an actual inlaid opal fragment, making each coin fractionally unique in its play of color.

Coober Pedy itself was named from the Aboriginal term "kupa piti," loosely meaning "white man in a hole" — a reference to the early miners who dug not just for opals but to live underground, escaping summer temperatures that routinely exceed 50°C.