The conservation of a corroded copper lump revealed the presence of ten necklace beads still threaded on the original string. The treatment is described. The beads, from the District of Nariño, Columbia, were analyzed using x-ray fluorescence, atomic absorption spectrophotometry, and electron probe microanalysis. The beads are made of an arsenical copper, and in one case, a tin bronze, an alloy not previously reported from ancient Columbia. The results of the analyses are discussed.