Kinichilite

Chemical formula: Mg<sub>0.5</sub>Mn<sup>2+</sup>Fe<sup>3+</sup>(Te<sup>4+</sup>O<sub>3</sub>)<sub>3</sub>·4.5H<sub>2</sub>O

Kinichilite is a very rare, hydrated magnesium, manganese, and iron tellurite, forming microscopic, yellowish-green crystals.

## Characteristics Kinichilite is an extremely rare mineral from the tellurite group. It occurs as very small, tabular or bladed crystals, rarely exceeding 0.2 mm in length. These crystals often form rosette-like or radial aggregates. Due to its microscopic size, its visual characteristics are difficult to observe without magnification. ## Physical Properties Kinichilite crystals exhibit a vitreous luster. They are transparent to translucent. Hardness and density have not been precisely measured due to the small size of the samples, but the density calculated based on the formula and cell parameters is 3.73 g/cm³. ## Colors and Varieties This mineral is characterized by a vivid yellowish-green color. No varieties have been reported. ## History and Name Kinichilite was discovered in the Bambollita (La Oriental) mine in Moctezuma, Sonora, Mexico. It was described in 1980 by Sidney A. Williams. The mineral's name comes from the Mayan word "kinich," meaning "sun," in reference to its sunny-yellow color and high tellurium content (Tellus - Latin for Earth). ## Uses Kinichilite has no industrial application. Its significance is purely scientific and as a collector's item, as an exceptionally rare tellurite.

Properties

Luster
Vitreous
Streak
Light yellow
Density
3.73
Cleavage
Perfect on {0001}
Fracture
Uneven
Transparency
Transparent to translucent
Crystal system
Trigonal

Diagnostic features

## Identification Identification of kinichilite is practically only possible using advanced laboratory methods, such as X-ray diffraction (XRD) and chemical analysis (EDS/WDS). Preliminary identification in a collection is based on its characteristic yellowish-green color, the form of microscopic, tabular crystals forming aggregates, and its co-occurrence with other rare tellurites and tellurides in known localities. ## Distinguishing from Similar Minerals It can be confused with other secondary, yellow or green tellurium minerals, such as emmonsite, mackayite, or poughite. Definitive differentiation requires chemical analysis, as all these minerals occur in similar parageneses and have a similar appearance at the micro-scale. ## Crystal Forms Kinichilite forms very small, thin, tabular crystals with a hexagonal outline, flattened parallel to {001}. These crystals often combine into radial or rosette-like aggregates.

Geological environment

## Genesis Kinichilite is a secondary mineral, forming in the oxidation zones (gossans) of hydrothermal deposits rich in tellurium. It forms as a product of the weathering of primary tellurides under low-temperature and low-pressure conditions. ## Mineral Associations It most commonly co-occurs with other tellurium minerals, such as native tellurium, emmonsite, mackayite, poughite, as well as with quartz, barite, jarosite, and hematite. ## Localities The only confirmed and described occurrence of kinichilite in the world is its type locality - the Bambollita (La Oriental) mine in the municipality of Moctezuma, Sonora state, Mexico.

Rarity

Extremely rare

For collectors

## Quality Criteria The quality of a kinichilite specimen primarily depends on the richness and aesthetics of the microscopic aggregates. Most valued are samples with clearly formed, rosette-like clusters of intensely colored crystals, contrasting with the surrounding rock (most often quartz). The size of the crystals, although always microscopic, is also important – larger and better-formed plates are more highly rated. ## Popular Localities All known collector specimens come from a single location worldwide: the Bambollita mine in Moctezuma (Mexico). This locality is known for the occurrence of many rare and unique tellurium minerals.

Care and storage

## Cleaning Kinichilite specimens are extremely delicate and small. Mechanical or chemical cleaning is not recommended. If necessary, compressed air (from a safe distance) can be used to remove dust. ## What to Avoid Avoid contact with water, chemicals, ultrasound, and sudden temperature changes. The crystals are brittle and easily damaged mechanically. ## Storage It is recommended to store specimens exclusively in specialized "micromount" boxes, protecting them from dust, shocks, and moisture. Avoid exposure to direct sunlight.

Sources

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