Mocha Stone

El Delfín del Corobicí

A moss agate pendant from Greater Nicoya

By Frederick W. Lange

Moss agate (also called mocha stone) is a semi-precious gemstone formed from silicon dioxide. This mineral is commonly found in limestone and granite. It is a form of agate that includes minerals of a green color embedded in the chalcedony, forming filaments and other patterns suggestive of moss. It also sometimes resembles blue cheese.

Most Greater Nicoya greenstone pendants were made from quartz and serpentine, and a small percentage were made from geological jade imported from the Motagua Valley of Guatemala, some 800 kilometers to the north. Very few artifacts are known that were made from moss agate — the pendant illustrated with this article being an almost unique example. This pendant was probably made from between 1,700 to 2,300 years ago and was manufactured using a combination of cutting, abrading, drilling and polishing techniques.

The uniqueness of the material that was utilized to manufacture the moss agate pendant suggests, at first impression, that the object may in fact be fake. But a careful examination of the proportions of the pendant and a microscopic analysis of the techniques by which the transverse suspension hole and the eyes were drilled indicates that the artifact is authentic. And, moss agate does appear in Greater Nicoya and has been identified in at least one case as a boulder from which preliminary blocks that were to be made into pendants were being prepared.

Despite the infrequency of itsuse, why was moss agate selected at least this once as a lapidary material in Greater Nicoya? Was it because of the visual impression that vegetal material is actually encased in the stone? Was the moss agate thought to be like amber, which the Native Americans also utilized to form effigy figures of animals and which often has insects encased in it? Despite its name, we know that moss agate does not contain organic matter and is usually formed from weathered volcanic rocks.

But let’s explore outside the usual interpretative box for a moment. Perhaps as much as 95 percent of the prehistoric record has disappeared and — like great detectives — we are left with the remaining 5 percent to attempt to interpret the activities and beliefs of the prehistoric past. Usually, our attempts at interpretation are tightly constrained by that 5 percent, to which we apply testable hypotheses and statistical analyses of probability.

But what if? Certainly, we today find the moss agate’s pattern attractive and rocks of this type are part of most geological collections. We can assume that some prehistoric lapidary specialist may have felt the same. And what if that lapidary specialist thought the green veining was in fact a small miniature forest that had been trapped in the rock? Mary Helms, a professor of anthropology at the University of North Carolina at Greensboro, has suggested that in western Panama chiefs utilized foreign styles of gold artifacts to convince their followers that they had contacts with the gods. Perhaps this moss agate pendant had been made for, and belonged to, a chief or shaman who employed its unique visual qualities to demonstrate similar contacts with the gods of Greater Nicoya. Just a thought.

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Dr. Frederick W. Lange has a doctoral degree in anthropology, awarded by the University of Wisconsin-Madison in 1971. He is the author of the book Before Guanacaste (2006), a popular account of the first 10,000 years of this part of Central America. BG is available at the Jaime Peligro Book Store in Tamarindo, the Café Britt Book Store at Peninsula de Papagayo, and in Libreria Internacional bookstores in San Jose and throughout Costa Rica. Fred’s e-mail address is hormiga_1999@yahoo.com