In Socorro, the New Mexico School of Mines (now New Mexico Tech) tested a sample from the purported impact site of a green fireball that had fallen on July 24, 1949 and found that it was rich in copper, an element that when burned, turns bright green. Source
Dr. Lincolm LaPaz found this highly significant, since copper burns with the same yellow-green color characteristic of the green fireballs. He also noted that if the copper particles came from the green fireballs, then they could not be conventional meteorites, since copper was never found in dust of meteoric origin. LaPaz suggested that further air and ground samples be taken in areas where the fireballs were seen. Source