Quetzalcoatlite

Chemical formula: Cu₂+₃Zn₂+₆Te₆+₂O₁₂(OH)₆·(Ag₁+,Pb₂+,&#₉₇₄₄;)Cl

This is a very rare zinc and copper tellurite, forming characteristic blue coatings and microscopic, acicular crystals.

## Characteristics Quetzalcoatlite is a complex zinc, copper, silver, and lead tellurite, belonging to a group of very rare minerals. It most often occurs as microcrystalline coatings, aggregates, and crusts of an intense blue or bluish-green color. It also forms small, acicular or hair-like crystals gathered in chaotic aggregates or small, radial rosettes. Due to its appearance and extreme rarity, it is a prized object in advanced micromineral collections. ## Physical Properties Quetzalcoatlite crystals are extremely small and brittle. This mineral is characterized by a vitreous luster and is usually translucent. Its Mohs hardness is 3, which means it is relatively soft. The density is significantly higher than average, at approximately 6.1 g/cm³. ## Colors and Varieties The dominant and only known color of this mineral is an intense, bright blue, often described as “electric blue.” The hue can shift to bluish-green. No named varieties are distinguished. ## History and Name The mineral was discovered in the Bambollita mine in Moctezuma, Sonora, Mexico. It was described in 1973 by Sidney A. Williams and Richard A. Bideaux. The name comes from Quetzalcoatl, the feathered serpent, a deity of the Aztecs and Toltecs, which is a reference to Mexico (the place of discovery) and the bluish-green color of the mineral, reminiscent of the feathers of the resplendent quetzal. ## Uses Quetzalcoatlite has no industrial application. Its only significance is scientific and collector-related – it is a sought-after and valuable acquisition for specialized collections of rare minerals and microminerals.

Properties

Mohs hardness: 3
Luster: Vitreous
Streak: Light blue
Density: 6.1
Cleavage: None
Fracture: Uneven
Transparency: Translucent
Crystal system: Trigonal

Diagnostic features

## Identification A characteristic feature of quetzalcoatlite is its intense blue color and its occurrence in the form of small, acicular crystals forming coatings and aggregates. Due to the microscopic size of the crystals, certain identification is possible almost exclusively using advanced analytical methods, such as Raman spectroscopy or EDS analysis. ## Distinguishing from Similar Minerals Quetzalcoatlite is sometimes confused with other secondary blue copper minerals, such as chalcanthite, linarite, or azurite. It differs from them in crystal habit (usually acicular), environment of occurrence (oxidation zones of tellurium deposits), and significantly greater rarity. Unlike chalcanthite, it is not soluble in water. ## Crystal Forms It forms very fine, elongated, acicular crystals, often with a hexagonal cross-section. These crystals usually occur as tangled aggregates, crusts, coatings, or small, radial aggregates.

Geological environment

## Genesis Quetzalcoatlite is a secondary mineral, forming in the oxidation zones (gossans) of hydrothermal ore deposits that are rich in tellurium. It crystallizes as a result of the weathering of primary tellurides and sulfides under strongly oxidizing conditions. ## Mineral Associations It most often co-occurs with other rare tellurium minerals, such as native tellurium, hessite, emmonsite, as well as with quartz, barite, native gold, pyrite, and manganese minerals. In the type locality (Mexico), it was found with tellurium, quartz, barite, and hetaerolite. ## Localities The most important and historical locality is the Bambollita (La Oriental) mine in Moctezuma, Sonora, Mexico. This mineral has also been confirmed in several other places around the world, including the Grand Central mine in Tombstone, Arizona (USA), and the Trixie mine in Utah (USA). All these localities are known for the occurrence of rich tellurium parageneses.

Rarity

Very rare

For collectors

## Quality Criteria The most highly valued specimens are those with rich, intensely colored coatings of acicular crystals on a contrasting rock matrix. The size of the covered surface and minimal damage to the delicate crystals are important. Specimens with well-visible, though still microscopic, radial aggregates are particularly sought after. The presence of rare associated minerals, especially native gold, significantly increases the value of the specimen. ## Popular Localities By far the most classic and prized specimens come from the type locality – the Bambollita mine in Mexico. Specimens from Tombstone, Arizona, are also highly valued by collectors specializing in minerals from that locality.

Care and storage

## Cleaning Specimens should only be cleaned with compressed air to remove dust. Any contact with water, and especially with chemicals, is highly risky. The crystals are extremely brittle and delicate, so avoid touching them with anything, even a soft brush. ## What to Avoid Absolutely avoid contact with water, acids, detergents, and other chemical agents. The mineral is sensitive to changes in temperature and humidity. It should not be heated or exposed to direct sunlight, which can cause it to fade or degrade. ## Storage It is recommended to store specimens exclusively in sealed, airtight “micromount” boxes, which protect against dust, humidity, and mechanical damage. Display should take place under stable conditions, away from sources of heat and light.

External references

https://en.wikipedia.org/wiki/https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FQuetzalcoatlite