Opal Hunters Unearth Massive ‘Unicorn Pocket’ of Opal Worth $900,000 Down Under A brother and sister duo from Australia have fulfilled an epic quest began by their parents decades ago. The family have been in search of opal their whole lives. They recently hit the jackpot, stumbling on a “unicorn pocket” of opal in southern Queensland, west of Brisbane. Like rainbows frozen in time, opals are one of the rarest, most precious and sought after gemstones on earth. The siblings unearthed a gargantuan 150-kilogram (approx. 330-pound) haul of the precious gemstones in the outback at a sight called Yowah in March, fulfilling their family’s two-generation quest.