The use of jade in Mesoamerica for symbolic and ideological ritual was highly influenced by its rarity and value among pre-Columbian Mesoamerican cultures, such as the Olmec, the Maya, and the various groups in the Valley of Mexico. Although jade artifacts have been created and prized by many Mesoamerican peoples, the Motagua River valley in Guatemala was previously thought to be the sole source of jadeite in the region.
This extreme durability makes fine grained or fibrous jadeite and nephrite highly useful for Mesoamerican technology. It was often worked or carved as ornamental stones, a medium upon which glyphs were inscribed, or shaped into figurines, weapons, and other objects. Many jade artifacts crafted by later Mesoamerican civilizations appear cut from simple jade axes, implying that the earliest jadeite trade was based in utilitarian function.
Jade and Jadeite
In general terms, jade refers to two distinct minerals: nephrite, a calcium and magnesium rich amphibole mineral, and jadeite, a pyroxene rich in sodium and aluminum. A general misconception is that nephrite does not naturally exist in Mesoamerica. However, the Middle Motagua River Valley area that yields jadeite also yields nephrite although Mesoamerican artisans had less interest in working nephrite. Colloquially 'jade' objects in Mesoamerica are composed of jadeite, but may also refer to other similar-looking, relatively hard greenstones such as albitite, omphacite, chrysoprase, and quartzite.
Variation in color is largely due to variation in trace element composition. In other words, the types of trace elements and their quantities affect the overall color of the material. “Olmec Blue” jade, characterized by an icelike shade of pale blue, owes its unique color to the presence of iron and titanium, while the more typical green jade's color is due to the varying presence of sodium, aluminum, iron, and chromium. Translucence can vary as well, with specimens ranging from nearly clear to completely opaque.
Sources in Mesoamerica
The archaeological search for the Mesoamerican jade sources, which were largely lost at the time of the Maya collapse, began in 1799 when Alexander von Humboldt started his geological research in the New World. Von Humboldt sought to determine whether or not Neolithic jadeite celts excavated from European Megalithic archaeological sites like Stonehenge and Carnac shared sources with the similar looking jade celts from Mesoamerica (they do not).
The first discovery of in-situ jade quarries was made by archeologist Mary Lou Ridinger in 1974. Previous to this discovery, academic consensus had not been reached regarding the true source of jade used by the Maya and debate continued for some time after, though it is now accepted as the first conclusive discovery of the sources of jade that the Maya culture had used. Since the first discovery, Ridinger also discovered many varieties of Central American jadeite that had never before been seen, such as lilac jade and a variety of jadeite with pyrite inclusions.
From 1974 to 1996, the only documented source of jadeite in Mesoamerica was the lowland Motagua River valley. Research conducted by the Mesoamerican Jade Project of Harvard's Peabody Museum of Archaeology & Ethnology between 1977 and 2000 led to the identification of both the long lost 'Olmec Blue' mines, a discovery published by Mesoamerican Jade project Field Director Russell Seitz and his colleagues from the American Museum of Natural History in Antiquity in December 2001. In addition, they conducted geochemical dating of several ancient Maya lode mines and alluvial sources in the mountainous areas on both sides of the Motagua. Following their exposure by the torrential rains of Hurricane Mitch in 1998, alluvial cobbles of blue jade were traced up a southern Motagua tributary, the Rio Tambor, to massive outcrops of fine grained translucent 'Olmec Blue' jadeite, at elevations of between 1200 and 3800 feet in the province of Jalapa, along a fault extending from Carrizal Grande to La Ceiba. Geochemical dating revealed that the southern deposits, including the archaeologically important translucent blue jade, were ~40 MA older that the coarse grained opaque jades mined for sale to tourists, or those from the higher elevations around a northern Motagua tributary, the Rio Blanco, where jadeite outcrops are found at elevations of up to an elevation of 6,000 feet and several of the ancient mining sites are connected by dry-laid stone paths.