Opals are rare and beautiful gemstones that feature a kaleidoscope of colors. Australia's Outback is home to more than 90 percent of the world's opals. People come from all over the globe hoping to strike opal and make their fortune.

The work of opal mining is grueling and dangerous, conditions are harsh, and failure rates are high. Less than 5 percent of miners ever strike it rich. However, fascination with the gemstone is at the root of "opal fever," which compels miners to risk life and limb and suffer many hardships in pursuit of the treasured gems. According to writer Patrick O'Brien, when opal fever takes hold, "no waterless countryside is too barren or inhospitable, no opal level is too impenetrable and no risk of failure and consequent financial ruin is strong enough to sway them [miners] from their chosen path."

Opal Towns

Australia's opal fields form a...