People from around the world travel to Coober Pedy, Australia, with hopes of getting rich. This town is full of valuable stones called 'opals'. Some opals are worth millions, but they are extremely hard to find. What influences the value of an opal? What does it take to find them? "The Footprint Reading Library" is the first non-fiction reading series for English language learners to present real-world stories in print, audio, and video. This series offers fascinating stories and facts from across the planet, and develops the language and skills needed to understand non-fiction writing. It offers a rich selection of engaging non-fiction, grouped into five themes: Incredible Animals, Fascinating Places, Remarkable People, Exciting Activities, and Amazing Science. One hundred individual readers are graded into eight levels - from Pre-Intermediate to Advanced. It ranges from 800 to 3,000 headwords.