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Magdalena, Jalisco, México.
For the ancient peoples of Mexico, the opal was given the name “Vitzitziltecpal” or Hummingbird Stone. They gave the stones this name because of their similarity to the brilliant iridescence of the plumage of the hummingbirds they were so fond of. Opals were highly regarded in Mesoamerican cultures for jewellery for nobles and high priests. According to historic studies, the Aztecs used opals were in their ceremonial ornaments, an act that implies there was an archaic industry for their extraction. Incredibly, the Spaniards showed no interest in these beautiful gems, possibly because they were obsessed with finding silver and gold, and the mining of these stones was abandoned.
It was not until 1840, that Don José María Siurab rediscovered the opal deposits and decided to begin extracting them from the Santa María Iris Mine. This was situated in the Hacienda Esmeralda near to the City of Queretaro in the centre of the country. Fifteen years later, a new deposit was found and La Carbonera Mine, among others, was opened. In the state of Queretaro the opal deposits are primarily located in Sierra de la Llave and spanning the three municipalities of Colón, Tequisquiapan and Ezequiel Montes.
The precious Mexican opals started to be recognized by European geologists at the beginning of the XIX century during the discovery of the various veins in Queretaro, Guerrero, Guanajuato, Chihuahua, San Luis Potosí and Hidalgo. The opal district of Tequiquiapan became the most productive reaching its heyday in the 1970’s due to the demand for opals from Europe and Asia. Other locations also gained success with the production of these amazing gems that resemble glowing coals or bits of the sun. One of these mines was the Magdelena Mine in Jalisco, located at a height of 1675 metres above sea level. This deposit was unknown until 1957, when Alfonso Ramírez discovered the first opal mine in Jalisco. Called La Única, it is located on the slopes of the volcano Tequila near to the Huizicilapan Ranch in the municipality of Magdalena.
In Pre-Colonial times, the place was known as Xochitepec or Monte Florido (which means Mount Flora), a zone governed by a mighty and powerful leader who liked to clad in opals called Goaxicar. Francisco Cortéz, a Spanish conquerer arrived to this region in 1524, in search of mines and a route to the Pacific from the Bajio. The path, which crossed the sierra, began in the domains of the local government. Goaxicar rose up in arms and a bloody battle ensued. Goaxicar was defeated and as a demonstration of his loyalty to the Crown he allowed his daughter to be evangelized. The Princess was given the Christian name Magdalena, which was in turn adopted by the community they inhabited.
The Magdalena Opal Zone occupies a rectangular area of 3000 sq. kilometres. In each sector there are separate deposits exhibiting different characteristics. In the area of San Simon, in the outskirts of Magdalena the most important mines are located: La Lupita, San Simon, San Martin, Santa Cecilia, Santo Niño, La Floreña, La Calavera, La Rosita, El Torero, San José, El Huaxical, La Mexicana, Hostotipaquillo, La Pelusera and La Florena.
Since the middle of the 1960’s, the production of opal in these mines surpassed that of the mines of Queretaro. There was a period of bonanza during which several mines emerged. The pieces that were found for use in jewellery are distinguishable in colour of the matrix and for the interplay of colour that include: jet black, blood red, fire red, RAIN RED, peacock blue, RAIN BLUE, and emerald green. Magdalena has been categorized for its opals that exhibit this interplay of bright colours, whereas those from Queretaro are basically fire opals.
The recollection of opals is the main economic activity of Magdalena. In every mine there are up to 200 workers involved in the excavation process, and a group of people called “pepenadores” (scavengers), who make a living by sifting through the stones that are considered to be waste. The quality pieces are cut and polished ready to be used in jewellery or for sale to the collectors. Every day the “opaleros” or the scavengers of opal remnants, congregate in front of the temple to sell their wares to any passers by. They place the small opals, often fragments of opal still in its rocky matrix, in small bottles filled with water. Whilst the unpolished stones are submerged in water their sparks of colour are more apparent.

Luis Lyons photo

Luis Lyons photo

 

Opals are formed over a period of over millions of years, in superficial deposits of rhyolites rich in silica hydrothermal solutions. The fluid seeps down through the rocks, into cavities formed by gases. Over time the fluid gels, sometimes containing different inclusions such as hornblende, geothyite, quartz cristobalite or pyrite, and is deposited inside the cavities. Eventually this hardens to form opals. Even though the origin of this mineral is volcanic it is fragile and requires careful handling. This is on account of its composition of silicon dioxide with water, the content of the latter oscillating between four and nine percent but which can be as high as twenty percent.


According to the classification of Strunz, opal is a mineral from the group of oxide and although it is not quartz, its composition is very similar. Until 2007, it was considered to be a valid mineral species, but actually it is not since it is made up of crystobalite with amorphous silica composed of silicon dioxide, which is quartz; coinciding in its composition but differing in its crystalline structure. Its microscopic particles, with a diameter of approximately 0.1 um (1/10000 millimetre), are found in structures packed in a three dimensional lattice. Because of this precise lattice it is the only gem capable of reflecting light waves. There are actually 80 opal mines in Magdalena, with 13 veins of obsidian, three of which are rainbow obsidian, and several other veins of different minerals. The opal specimens from this region are highly appreciated both by collectors and jewellers and for this reason it is acknowledged as the opal capital of the world.