Burrowing deep underground, thousands of informal miners risk their lives to find gleaming red gems as a law change spurs opportunity in Myanmar's "land of rubies".Emperors, kings and warlords have long fought over the valley of Mogok in Mandalay region, where the unique "pigeon-blood" stones lie hidden.The Mogok rubies are the most expensive in the world, with the highest-quality jewels fetching multi-million-dollar prices in an industry notoriously bereft of regulat