Gems and Gemstones
Gems and Gemstones
Gems and Gemstones have been important to both the early development and the present-day economy in several key areas of South America. Brazil now has the leading gemstone industry in Latin America, including mining, cutting, polishing, setting, marketing, and exporting.
Archaeological discoveries in Colombia have revealed the use of emeralds in pre-Columbian jewelry. Early accounts of the ceremonies that took place at Lake Guatavita, high in the Andes Mountains of Colombia, describe the use of both gold andemeralds as offerings thrown into the sacred lake. Soon after the arrival of the Spanish conquistadores, emeralds were being traded as far north as Mexico and as far south as Chile. Emeralds were soon discovered in the areas of Muzo and Chivor, located north and northeast of Bogotá. Chivor was particularly well known to the early Spaniards, who employed thousands of local Indians as slave labor. In the early seventeenth century, word of the brutal working conditions at Chivor resulted in both royal and papal decrees prohibiting the use of Indian slave labor, and the mines were forced to close. Both Muzo and Chivor have had a violent and checkered history since colonial times. Both mines are known to produce among the finest emeralds in the world, yet the mines have rarely been worked at a profit. In the 1970s, however, the government opened Muzo to private mining ventures, the operations of which have been relatively successful. Chivor remains less developed. Both areas retain an unfortunate reputation for violence because of anarchy among the independent miners. In 1976, an estimated 50,000 people were killed. Economic statistics are difficult to maintain, largely because of significant production from the independent miners, (guaqueros) of the area. It is certain, however, that emeralds are a very important part of the Colombian economy.
Today, Colombian emeralds can be seen in the crown jewels of the world as well as in the finest jewelry stores. Particularly important historic collections of Colombian emeralds are among the treasures of the Topkapi Museum in Istanbul, Turkey, and in the crown jewels of Iran. Many of these fine, historic emeralds made their way around the world. In the late sixteenth century, the Spanish brought back from the New World large quantities of emeralds, with which they reportedly flooded the emerald markets in Europe. Europeans, in turn, found a willing market with the Mogul rulers of India. The Moguls were particularly fond of carving large gems and attaching them to clothing. In 1739, however, invading Persian armies sacked the Mogul treasuries of Delhi and brought enormous quantities of emeralds back to the Middle East, where many remain today. Additional deposits of emeralds were discovered in Brazil in the 1960s, and are currently mined in Goiás and Bahia.
Diamonds became an important part of the Brazilian economy in the mid-eighteenth century, after they were discovered in the river gravels around the town of Diamantina in the state of Minas Gerais in 1725. The world's production had previously come from the famous mines around Golconda in India. By the eighteenth century, however, these Indian mines were nearing depletion. The discovery of the Brazilian deposits shifted world attention on Brazil. The Portuguese explorer Sebastino Leme do Prado, who had previously lived in India, is credited with the first identification of diamonds in Brazil. It is reported that the diamonds were being used by local gold miners as chips in card games. These "chips" were sent off to Amsterdam for appraisal and the diamond-bearing area was immediately declared crown property. In its height of production in 1851, as many as 300,000 carats were mined annually from the Diamantina area as well as from a new find in the state of Bahia. The diamonds were recovered from the alluvial river gravels solely by panning. Gold commonly accompanied the diamonds. Several important diamonds were recovered from these river gravels, including the 726.6-carat Presidente Vargas Diamond, which was discovered in 1938.
By the 1880s, however, Brazil could not keep up with the world demand for diamonds. At the same time, the huge diamond deposits of southern Africa were discovered, and attention shifted away from Brazil. There is no doubt that diamonds had a significant impact on the Brazilian economy of the late eighteenth and early nineteenth centuries. Today, huge dredges still mine the gravels around Diamantina for gold and diamonds, although on a world scale, production is insignificant.
No other gem materials could be considered of importance until the outbreak of World War II. The great demand for "strategic" minerals such as quartz and tourmaline prompted a massive exploration program throughout South America. Success, however, was focused on the state of Minas Gerais in Brazil. Minas Gerais is rich in granite geologic formations known as pegmatites. These pegmatites are sometimes called "nature's jewel box" because of the vast array of gemstones that they may contain. In addition to the strategically important quartz and tourmaline, pegmatites are home to topaz, aquamarine and morganite beryl, kunzite, and many different species of garnet. While most of these gems were overlooked in favor of the relatively more important strategic minerals for the war effort, the end of the war brought on massive gem-mining programs. Today, the majority of the world's supply of quartz, tourmaline, topaz, garnet, kunzite, and beryl come from Brazil.
Other areas of South America that can be considered of importance to today's gem market, but that have had little if any importance historically, include the great agate and amethyst deposits near Artigas, Uruguay, and bordering Rio Grande do Sul, Brazil. Huge quantities are mined from the basaltic lava flows to supply the gem markets around the world. Amethyst is also mined in Minas Gerais and Bahia. Opals that rival those from Australia come from Piauí, Brazil. Argentina is known for small quantities of "stalactitic" rhodochrosite, sometimes known as "Inca Rose." Venezuela is a minor producer of diamonds, and Chile of lapis lazuli.
Central America has produced a limited variety of gem materials historically, though some have been recovered in significant amounts. Most notable are the jade deposits near the Palmilla River in Guatemala, which were worked in pre-Columbian times. Artifacts made of jade from this region have surfaced throughout Mexico to the north and into Colombia to the south. In recent times, the Dominican Republic has supplied a good portion of the world's amber market.
Mexico has produced significant supplies of opal. This opal tends to have an orange body color with or without fire, or play of color. It can also be red and is sometimes called fire opal. Fire opals have been produced only since the late nineteenth century, although they may have been known to the Aztecs. Most of the opals come from the mines near Querétaro.
S. H. Ball, "Historical Notes on Gem Mining," in Economic Geology 26 (1931): 681-738.
Peter W. Rainier, Green Fire (1942).
R. Maillard, Diamonds: Myth, Magic, and Reality (1980).
Peter C. Keller, "Emeralds of Colombia," in Gems and Gemology 17 (1981): 80-92.
K. Proctor, "Gem Pegmatites of Minas Gerais, Brazil," in Gems and Gemology 20 (1984): 78-100.
Carvalho, Fábio Lamachia. Sonho verde: Aventura num garimpo de esmeraldas. São Paulo: Geração, 2002.
Santos, Márcio. Estradas reais: Introdução ao estudo dos caminhos do ouro e do diamante no Brasil. Belo Horizonte: Editora Estrada Real, 2001.
Peter C. Keller