A publication of the Archaeological Institute of America
Tests have revealed that a small stone figurine bequeathed to the Hudson Museum at the University of Maine is the oldest known emerald from Mesoamerica and the only known Precolumbian carved emerald. The stone, emerald green with many small areas of blackish-green and yellow mottling, was carved into the shape of a standing man with straight cuts and then polished. The man's hands are folded over his midsection and he wears a short apron and head gear. Conical drilled holes pass through the figure under the arm pits and from side to side through the neck, perhaps so that it could be suspended on a cord. The figure (HM 601) is 2.2-inches (5.63 cm) tall and weighs 118.5 carats (23.7 g).
The stone was given to the university by alumnus William P. Palmer III in 1982. An index card which came with the artifact states:
Emerald figure of a man. To the best of my knowledge the only Emerald carved in the round piece in existance [sic] of Pre-Columbian origin. Area unknown. 500 B.C. to 250 A.D.
The same card indicates the piece is Olmec, was purchased or delivered March 30, 1968, and was originally numbered 284 M. Palmer bought objects numbered in this way from a New York City dealer.
No tests, however, had ever been conducted to verify that it was an emerald, and because the figurine has no known provenience its Olmec attribution was based only on the style of the carving. We performed a battery of nondestructive tests, from visual and microscopic examination to spectral and trace element analysis, to determine whether or not the stone was an emerald and, if so, whether it was a natural stone or a synthetic one, indicating a fake. Emeralds come from only a few localities around the world, the most important being Colombia, and their physical characteristics vary depending on locality. The overall appearance and color of the stone are consistent with a natural emerald rather than an epoxy fake. The stone's refractive index (the ratio between the velocity of light passing through a vacuum and light passing through emerald) is within the range of natural emerald. When the stone is viewed through a Chelsea filter, which absorbs most visible light but transmits the long red wavelengths and a band in the yellow-green portion of the spectrum, a definite reddish area, consistent with natural emerald from Colombia and Russia, appears at the edge of the right shoulder.
The stone's spectrum, determined with energy-dispersive X-rays in a scanning electron microscope by Tiina Hallamaa and Pierre Lepoutre of the Paper Surface Science Program at the University of Maine, is consistent with emerald. We found through X-ray fluorescence that the figurine shares more trace elements, including copper, barium, zinc, rubidium, and titanium, with the Muzo, Colombia source than with any other. The figurine gave off a red glow under long-wave ultraviolet light in the area of the waist and below on the front and from the shoulders to the legs on the back. While this glow is typical of synthetic emeralds, it also characterizes emeralds from the Chivor, Colombia source. Under short-wave ultraviolet light, 98 percent of the surface gave off a purplish-red glow, which is characteristic of true emeralds.
Uncorrected mistakes (the cutting tool slipped, leaving marks above the left hand and on the left thigh) and conical drill holes indicate that the stone carver was using hand tools without the aid of magnification, suggesting it is a Precolumbian work. How the emerald was cut is unknown.
The figurine's general appearance is similar to some small stone figures made by the Olmec of the Gulf Coast of Mexico during the period from 900 to 600 B.C., but it lacks certain facial characteristics--a V-shaped forehead indentation, and a baby face featuring a mouth with the corners turned downward in a cry or snarl, and a prominent upper lip and toothless gums--which would make that identification certain. It has stronger similarities to contemporaneous stone figures carved in Guerrero, Mexico, including the arms folded over the belly and the nose and mouth formed by horizontal divisions within a trapezoid. Mesoamericanists have not agreed about the relationship between Guerrero and the Olmec heartland. Where exactly the emerald was excavated is unknown to us, but soil remaining within cuts on it could be chemically matched to a particular site.
Colombia was the only source of emeralds in the Western Hemisphere that was known for certain at the time of the Conquest. Emeralds were traded as far south as Bolivia and as far north as Mexico. It would have been a simple matter for a trader to carry a small emerald from Colombia to Mexico on foot or by boat along the Pacific coast, or it could have been passed from hand to hand.
Colombian sources were being mined earlier than A.D. 1000, and polished emeralds were found in graves at Sitio Conte, Panama, dated A.D. 700-900. It now appears that the Muzo source was being mined nearly two millennia earlier. Emeralds occasionally come from secondary deposits produced by weathering or other decomposition of the emerald-bearing matrix, rather than from mines, but such deposits are rare. One is located at Ganchalá, Colombia, but its trace elements are not as close a match as Muzo's.
There is only one description of another Precolumbian emerald which might have been carved. During the Conquest, Cortés sent emeralds from Mexico to the Spanish court, including one from the Hall of Justice in Texcoco which was reported to be shaped like a pyramid and as broad as the palm of the hand. The object disappeared en route to Spain and the accuracy of the description cannot be verified.
Stephen Whittington of the Hudson Museum, gemologist James Vose, and Charles Hess of the University of Maine are the authors of this newsbrief.