Clinoungemachite

Chemical formula: K₃Na₈Fe³⁺(S⁶⁺O₄)₆(OH)₂·10H₂O

Clinoungemachite is a rare, hydrated iron, sodium, and potassium sulfate, forming tiny, colorless to pale yellow crystals in the shape of needles and tabular forms.

## Characteristics Clinoungemachite is a complex, hydrated iron, sodium, and potassium sulfate, belonging to the ungemachite group. It occurs as very small, acicular or tabular crystals, rarely exceeding 1 mm in length. It typically forms radial aggregates, rosettes, or appears as coatings and crusts on other minerals. ## Physical Properties The crystals are transparent and exhibit a vitreous luster. Due to its small size and rarity, many of its physical properties, such as hardness, density, or cleavage, have not been precisely determined. ## Colors and Varieties This mineral is colorless to pale yellow. No varieties have been distinguished. ## History and Name Clinoungemachite was described as a new mineral in 1980 by Joseph A. Mandarino, B. D. Sturman, and P. J. Dunn. Its name refers to its monoclinic crystallographic system and its structural relationship to ungemachite, another sulfate named after the Belgian mineralogist Henri Ungemach.

Properties

Luster
Vitreous
Density
0
Transparency
Transparent
Crystal system
Monoclinic

Diagnostic features

## Identification Identification of clinoungemachite is primarily based on its characteristic appearance – tiny, acicular or tabular crystals forming radial aggregates. Its origin from a unique geological environment (oxidized sulfide deposits in a desert climate) and its co-occurrence with other rare sulfates are also crucial. ## Distinguishing from Similar Minerals It can be confused with other secondary sulfates, such as ungemachite, metasideronatrite, or metavoltine. Ungemachite crystallizes in the trigonal system, in contrast to the monoclinic clinoungemachite, but distinguishing these minerals without advanced analytical methods (XRD) is practically impossible. ## Crystal Forms Clinoungemachite forms elongated, acicular crystals or flattened, tabular forms. These crystals often combine into radial aggregates, rosettes, or form delicate coatings on the surface of the host rock.

Geological environment

## Genesis Clinoungemachite is a secondary mineral, forming in the oxidation (weathering) zones of sulfide deposits, especially in extremely arid, desert conditions. It forms as a result of reactions between sulfate-rich solutions and minerals containing iron, sodium, and potassium. ## Mineral Associations This mineral co-occurs with other rare, secondary sulfates, such as ungemachite, metasideronatrite, metavoltine, sideronatrite, tamarugite, coquimbite, and chalcanthite. ## Localities The most important and type locality for clinoungemachite is the Chuquicamata mine in the Antofagasta region of Chile. This is the world's largest open-pit copper mine, known for the occurrence of many rare secondary minerals.

Rarity

Very rare

For collectors

## Quality Criteria The quality of clinoungemachite specimens is primarily assessed based on the richness and aesthetics of the crystal aggregates. Most valued are specimens with well-formed, distinct rosettes or radial clusters of acicular crystals, contrasting with the rock matrix. Due to the microscopic size of the crystals, their abundance on the specimen is key. ## Popular Localities The only known and commercially significant source of clinoungemachite specimens is the Chuquicamata mine in Chile. Specimens from this locality are the standard for this mineral.

Care and storage

## Cleaning Due to the extreme fragility and small size of the crystals, mechanical cleaning is not recommended. If absolutely necessary, compressed air can be used from a safe distance to remove loose dust. Avoid contact with water, which can dissolve the mineral. ## What to Avoid Absolutely avoid contact with water, water vapor, and all chemicals. The mineral is sensitive to changes in humidity and temperature. It should not be exposed to direct sunlight. ## Storage Clinoungemachite specimens should be stored in tightly sealed containers or "micromount" boxes to protect them from moisture, dust, and mechanical damage. It is best to store them in a dry place with a stable temperature.

External references

Sources

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