Researchers at the Smithsonian Tropical Research Institute in Panama said the placement and unusual composition of a cluster of 12 stones, dated as at least 4,000 years old, suggests they were used by a shaman or healer.
Charcoal found directly underneath the cache of stones in the back of a small, prehistoric rock-shelter was radiocarbon dated to 4,800 years ago, while a second fragment of charcoal in a level above the stones was dated to 4,000 years ago, a Smithsonian release reported Monday.
"There was no evidence of a disturbance or pit feature to suggest someone had come along, dug a hole and buried the stones at a later date," said Ruth Dickau, a post-doctoral researcher from the University of Exeter in Britain. "The fact that the stones were found in a tight pile suggests they were probably deposited inside a bag or basket, which subsequently decomposed."
Shamans or healers belonging to early peoples in Central and South America often included special stones among the objects they used for ritual practices, the researchers said.
Although the rocks and crystals found in the rock shelter are commonly associated with gold deposits in Central America, they said, there is no evidence the stones were collected in the course of gold prospecting.
"But the collector of the stones clearly had an eye for unusual stones and crystals with a special significance whose meaning is lost to us," geologist Stewart Redwood said.