Dozyite

Chemical formula: Mg₇Al₂(Si₄Al₂)O₁₅(OH)₁₂

Dozyite is a very rare mineral from the serpentine group, a hydrated magnesium aluminum silicate, forming microscopic, white flakes.

## Characteristics Dozyite is a hydrated magnesium aluminum silicate belonging to the serpentine group. It occurs as extremely small, platy crystals with a hexagonal outline, usually not exceeding 20 micrometers in diameter and 1 micrometer in thickness. It forms aggregates with a pearly luster, resembling talc or fine-grained mica. Due to the microscopic size of its crystals, its macroscopic features are difficult to observe, and identification requires advanced analytical techniques. ## Physical Properties Dozyite crystals are flexible, which is typical for minerals with a layered structure. The Mohs hardness is very low, at 2.5, similar to other clay minerals. The luster observed on aggregates is pearly. It is a very light mineral, with a calculated density of 2.63 g/cm³. ## Colors and Varieties Dozyite is colorless in single crystals, but in aggregates, it appears white. No varieties have been distinguished. ## History and Name The mineral was described in 1995 by G.O. Bailey, J.F. Banfield, W.W. Barker, and R.C. Morris. Its name honors Jean-Jacques Dozy (1908-2004), a Dutch geologist who, in 1936, discovered the Ertsberg copper and gold deposit in Indonesia, where dozyite was first identified. This discovery was crucial for the development of one of the world's largest mining complexes – the Grasberg mine. ## Uses Dozyite has no industrial or commercial applications. Its significance is purely scientific and as a collector's item, as a rare member of the serpentine group.

Properties

Mohs hardness
2.5
Color
Colourless, violet
Luster
Pearly
Streak
White
Density
2.66
Cleavage
Perfect on {001}
Fracture
Micaceous
Transparency
Translucent
Crystal system
Monoclinic

Diagnostic features

## Identification Macroscopic identification of dozyite is practically impossible. It is identified based on its co-occurrence with other minerals in a specific geological environment (skarn zones). Definitive identification requires advanced methods such as X-ray diffraction (XRD) and chemical analysis (e.g., electron microprobe), which allow for the determination of its unique structure and chemical composition. ## Distinguishing from Similar Minerals Dozyite in aggregate form can be macroscopically indistinguishable from talc, muscovite, kaolinite, or chlorite. It differs from them in its crystal structure and chemical composition, which can only be confirmed by laboratory methods. Unlike talc, it is not as distinctly greasy to the touch. ## Crystal Forms It forms microscopic, hexagonal flakes and plates. It occurs as rosette-like or platy aggregates, and as fine veins and coatings on other minerals.

Geological environment

## Genesis Dozyite is a low-temperature hydrothermal mineral. It forms in contact metamorphic zones, within magnesium skarns that have undergone later hydrothermal processes. It forms as a result of reactions between hydrothermal solutions and dolomite and other magnesium-rich rocks. ## Mineral Associations This mineral co-occurs with antigorite, lizardite, chlorite, dolomite, anhydrite, talc, quartz, chalcopyrite, and pyrite. ## Localities The most important and type locality for dozyite is the Ertsberg-Grasberg mining complex in Papua Province, Indonesia. This is the only confirmed and well-documented locality for this mineral in the world.

Rarity

Very rare

For collectors

## Quality Criteria The quality of dozyite specimens is primarily assessed based on the richness and visibility of aggregates on the rock matrix. Since it is a microscopic mineral, samples where white dozyite aggregates form a clear contrast with the darker host rock are most valued. Association with other well-formed minerals, such as chalcopyrite or quartz, is also important. ## Popular Localities The only source of collector specimens is the Ertsberg-Grasberg mine complex in Indonesia. Specimens from this locality are unique and represent the only opportunity to acquire this mineral for a collection.

Care and storage

## Cleaning Dozyite specimens should not be wet cleaned. Due to its extreme softness and delicacy, it is best to remove dust using compressed air from a safe distance or a very soft brush. Any mechanical contact can damage the microscopic crystals. ## What to Avoid Avoid contact with water, chemicals, acids, and detergents. The mineral is very soft and sensitive to scratches. It should be protected from high temperatures, which can cause water loss from its structure. ## Storage Dozyite specimens should be stored exclusively in sealed containers or classification boxes to protect them from dust, moisture, and mechanical damage. It is not suitable for display outside a closed container.

External references

Sources

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