During the 1970s and 1980s, treasure hunters discovered the centuries-old remains of the sunken Spanish galleons Nuestra Señora de Atocha and Santa Margarita. Not only did they find massive amounts of silver and gold in coins, bars, and chains, but they also uncovered a number of rough emeralds and several pieces of emerald-set jewelry. Recently, some of the treasures recovered from the Atocha were examined at the Santa Monica office of the GIA Gem Trade Laboratory. Gemological testing of the emeralds revealed inclusions typical of stones mined in Colombia as well as possible evidence of extended submersion in seawater. Study of the jewelry revealed a high-karat gold content and fine workmanship that represented methods typical of the era.
