On a Stone Shopping Spree in Sri LankaBuyers may not have realized it, but sapphire sales to the United States from one of the world’s oldest sources, Sri Lanka, are quietly booming.The United States is still the largest consumer market for Sri Lankan gemstones, buying nearly a quarter of all stones exported. According to Sri Lanka’s National Gem & Jewellery Authority, exports to the United States were valued at $7.62 million in the first quarter of 2012—a 102 percent growth from the prior year.One of the pits at the new primary sapphire mine near KataragamaBlue sapphires accounted for more than 75 percent of those stones: 11,642 carats to the tune of $5.77 million. That’s up from 9,825 carats worth $2.81 million—18 percent and 105 percent bumps from 2011’s first quarter. (Not surprisingly, the average blue sapphire per-carat price also jumped from $286 to $495.)Sri Lanka