In the decades after the 1966 crash of an Air India plane on Mont Blanc in Chamonix, France, the mountain’s ice and snow have been yielding bits of debris, such as photos, old newspapers, and in 1986 even a piece of a landing gear.
Then in 2013, a French mountain climber in his 20s made the dazzling discovery of a metal box containing 6,000 precious gemstones—mostly emeralds and sapphires—worth a staggering 300,000 euros ($339,000).