Legend had long held that emeralds used to decorate the crown of an Indian potentate and a Roman earring came from ancient mines in Austria or Egypt, but they in fact came from mines in Pakistan and Colombia that people had believed were only recently discovered, the researchers said. They also found that emeralds from Colombia, held by experts to be the finest in the world, were traded worldwide almost as soon as they were discovered by Spanish conquistadors in the 16th century.
Isotopes are slight variations of the elements.
Oxygen Variance the Key Giuliani said he and colleagues had been studying the development of emeralds in Brazil and Colombia, and discovered that they could pinpoint their origin by looking at these variations in oxygen, a major constituent of emeralds. They looked at a gold and emerald earring dating back to when Roman occupied France. We also studied the emerald from the Holy Crown of France, which was set on the central jewel lily of the crown of France by Louis IX, king of France between 1226 and 1270. They also looked at some geological specimens of emerald, as well as one salvaged from the wreck of the Atocha, a Spanish galleon that sank off Florida in 1622. The researchers used ion microprobe oxygen isotopic analysis, in which the emerald is bombarded with an electron ion beam.