Takovite

Chemical formula: Ni²⁺₆Al₂(OH)₁₆(CO₃)·4H₂O

Takovite is a rare, basic nickel and aluminum carbonate from the hydrotalcite group, forming soft, yellowish-green or bluish-green coatings and aggregates.

## Characteristics Takovite is a hydrated, basic nickel and aluminum carbonate, belonging to the hydrotalcite group. It most commonly occurs as very fine-grained, earthy or compact masses, as well as coatings and encrustations on other minerals. It rarely forms microscopic, hexagonal or trigonal platelets. Its appearance is usually inconspicuous, and macroscopic specimens are rare. ## Physical Properties This mineral is characterized by low hardness, measuring 2 on the Mohs scale, which means it is very soft and can be scratched with a fingernail. Its density is approximately 2.80 g/cm³. It is translucent, and its luster is described as waxy or dull, especially in the case of earthy aggregates. ## Colors and Varieties Takovite exhibits colors ranging from yellowish-green to bluish-green. The intensity and shade depend on impurities and crystallization conditions. No named varieties are distinguished. ## History and Name The mineral's name comes from its discovery locality – the Takovo deposit in Serbia. It was first described in 1957, and its discovery was approved in 1979. ## Uses Takovite has no industrial significance. It is solely an object of interest for collectors specializing in rare minerals or nickel minerals.

Properties

Mohs hardness
2
Luster
Waxy to dull
Streak
White to light green
Density
2.80
Cleavage
Perfect on {0001}
Fracture
Uneven
Transparency
Translucent
Crystal system
Trigonal

Diagnostic features

## Identification Takovite can be identified by its characteristic yellowish-green or bluish-green color, very low hardness (2 on the Mohs scale), and occurrence as earthy or waxy coatings and masses. It reacts with acids, which is a diagnostic feature for carbonates, but this test is destructive and not recommended for rare specimens. ## Distinguishing from Similar Minerals It can be confused with other secondary nickel minerals, such as reevesite, zaratite, or gaspeite. Differentiation requires advanced analytical methods, such as X-ray diffraction (XRD) or chemical analysis (EDS/WDS), as these minerals can be visually almost identical. ## Crystal Forms Takovite crystals are extremely rare and appear as microscopic, thin, hexagonal or trigonal platelets. It typically forms very fine-grained, compact or earthy aggregates, as well as thin coatings and crusts.

Geological environment

## Genesis Takovite is a secondary mineral, forming in the weathering (oxidation) zones of nickel-rich sulfide deposits, especially in serpentinites and other ultramafic rocks. It forms as a result of low-temperature hydrothermal processes or chemical weathering of primary minerals. ## Mineral Associations It often co-occurs with other secondary nickel and magnesium minerals, such as reevesite, hydrotalcite, serpentine, magnesite, chromite, and also with minerals from the spinel group. ## Localities The most important and type locality is Takovo in Serbia. It is also known from several other localities worldwide, including nickel mines in the Attica region of Greece; St. Jean-de-Moirans in France; the Carr Boyd Rocks mine in Western Australia; and the Honaker mine in Lancaster County, Pennsylvania, USA.

Rarity

Very rare

For collectors

## Quality Criteria The most valued specimens by collectors are those with clearly visible, rich aggregates of intense, uniform color. Due to its rarity, every documented specimen has collector's value. Specimens with well-formed, even microscopic, crystals are exceptionally sought after. Association with other rare minerals is also important. ## Popular Localities Specimens from the type locality, Takovo in Serbia, are the most classic and desirable. Material from Greek mines and Western Australia also appears on the collector's market.

Care and storage

## Cleaning Takovite specimens should be cleaned very carefully, preferably using compressed air to remove dust. Due to its extreme softness, any mechanical contact, including brushes, should be avoided. Contact with water is not recommended, as it can damage delicate, earthy aggregates. ## What to Avoid The mineral is sensitive to acids, which cause it to dissolve rapidly. It should be protected from moisture, chemicals, and high temperatures. Due to its low hardness, it is very susceptible to scratches and mechanical damage. ## Storage It is recommended to store takovite specimens in closed, padded collector's boxes to protect them from dust, moisture, and damage. It should not be displayed in areas with fluctuating humidity or temperature.

External references

Sources

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