Baileychlore

Chemical formula: (Zn<sup>2+</sup>,Fe<sup>2+</sup>,Al,Mg)<sub>6</sub>(Si,Al)<sub>4</sub>O<sub>10</sub>(OH)<sub>8</sub>

Baileychlor is a rare, green mineral from the chlorite group, being a hydrated zinc, iron, aluminum, and magnesium silicate.

## Characteristics Baileychlor is a mineral from the chlorite group, belonging to the silicate class. It usually occurs as very fine, scaly crystals that form compact or earthy aggregates. It is rarely observed in the form of distinct, hexagonal tabular crystals. Its structure and chemical composition are complex, with zinc as a key element distinguishing it from other chlorites. ## Physical Properties This mineral is very soft, with a Mohs hardness of approximately 2.5-3. It is light, with a density close to 3.2 g/cm³. Crystals exhibit perfect cleavage in one plane, which is typical for platy minerals such as micas and chlorites. The luster is dull, earthy, or pearly on cleavage surfaces. ## Colors and Varieties Baileychlor has a characteristic color ranging from olive-green to yellowish-green. No color or commercial varieties are distinguished. ## History and Name The mineral's name honors Professor Sturges W. Bailey (1919-1994) of the University of Wisconsin, USA, in recognition of his contributions to research on clay minerals and mica polymorphism. The mineral was described and approved as a new species in 1988. ## Uses Baileychlor has no industrial applications. It is solely an object of interest for collectors specializing in rare minerals and scientists studying hydrothermal processes and the oxidation zones of ore deposits.

Properties

Mohs hardness
2.5-3
Luster
Dull to pearly
Streak
Greenish-gray
Density
3.22
Cleavage
Perfect on {001}
Fracture
Uneven
Transparency
Translucent to opaque
Crystal system
Trigonal

Diagnostic features

## Identification Baileychlor is recognized by its characteristic green color, very low hardness, and finely scaly or earthy mode of occurrence. Perfect cleavage in one direction is a key feature, although difficult to observe in compact aggregates. Certain identification requires advanced analytical methods, such as X-ray diffraction (XRD) or chemical analysis (EDS/WDS). ## Distinguishing from Similar Minerals It can be confused with other green secondary minerals, such as glauconite, celadonite, or other chlorites (e.g., clinochlore, chamosite). Distinguishing it from other zinc silicates, like hemimorphite or willemite, is possible based on its significantly lower hardness. Its presence of zinc distinguishes it from common chlorites, which requires specialized testing. ## Crystal Forms Most often, it forms microscopic, hexagonal plates and scales that combine into compact, earthy, rosette-like, or spherulitic aggregates. Well-formed crystals visible to the naked eye are rarely found.

Geological environment

## Genesis Baileychlor is a secondary mineral, forming in the oxidation zones of hydrothermal ore deposits, especially those rich in zinc and iron. It forms as a result of the alteration of primary minerals under conditions of low temperatures and pressures. ## Mineral Associations It often co-occurs with other minerals from the oxidation zone. At the type locality (Red Dome, Queensland), it was found in association with quartz, calcite, pyrite, chalcopyrite, sphalerite, galena, anglesite, cerussite, hemimorphite, and goethite. ## Localities The most important and best-documented locality, which is also the type locality, is Red Dome, west of Chillagoe in Queensland, Australia. This is the only place from which well-characterized specimens of this mineral originate.

Rarity

Very rare

For collectors

## Quality Criteria The quality of a baileychlor specimen primarily depends on the richness and visibility of the aggregates on the rock matrix. The most prized specimens are those where the mineral forms distinct, rosette-like or spherulitic clusters of intense, olive-green color. Contrast with a light host rock (e.g., quartz) also enhances visual appeal. ## Popular Localities The only source of collector specimens is the Red Dome mine in Queensland, Australia. Material from this locality is considered reference for this species.

Care and storage

## Cleaning Baileychlor specimens are very delicate and soft. They should be cleaned only with a soft, dry brush to remove dust. The use of water, especially under pressure, can damage fine aggregates. ## What to Avoid Avoid contact with water, chemicals (especially acids), and ultrasonic cleaners. The mineral is susceptible to scratching and abrasion due to its low hardness. It should not be heated or exposed to prolonged strong light. ## Storage Specimens should be stored in separate, padded boxes or containers to avoid contact with harder minerals. It is best to display them in closed showcases, protecting them from dust and mechanical damage.

External references

Sources

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