Tredouxite

Chemical formula: Ni²⁺Sb⁵⁺₂O₆

Tredouxite is a very rare nickel and antimony oxide, forming microscopic, hexagonal crystals of an intensely green color.

## Characteristics Tredouxite is a mineral from the oxide group, belonging to the trigonal PbSb₂O₆ structural group. It occurs as extremely small, hexagonal, tabular crystals, rarely exceeding 50 micrometers in diameter and 10 micrometers in thickness. It also forms rosette-like aggregates and granular clusters. It is a secondary mineral, formed as a result of weathering processes. ## Physical Properties Tredouxite crystals exhibit a vitreous luster. Due to the microscopic size of the crystals, most physical properties, such as hardness or density, have not been precisely measured, but only calculated based on crystallographic data. The calculated density is approximately 6.45 g/cm³. ## Colors and Varieties This mineral is characterized by a vivid, emerald-green color. No varieties are known. ## History and Name The name Tredouxite comes from the Tredoux rock formation where this mineral was discovered. It was first described by C.L. Gneiss and approved by the International Mineralogical Association (IMA) in 2017 under number IMA2017-035. The type locality is Bon Accord farm in the Barberton district, South Africa. ## Applications Due to its extreme rarity and microscopic size, Tredouxite has no industrial applications. It is solely an object of scientific and collecting interest for micromineral specialists.

Properties

Mohs hardness
3
Color
Light gray
Luster
Vitreous
Streak
Gray
Density
6.45
Cleavage
Perfect on {0001}
Transparency
Translucent
Crystal system
Tetragonal

Diagnostic features

## Identification Field identification of Tredouxite is impossible. Identification requires advanced laboratory techniques, such as scanning electron microscopy (SEM) with EDS analysis or X-ray diffraction (XRD). Visual characteristics under high magnification include the distinctive emerald-green color and hexagonal, tabular crystal habit. ## Distinguishing from Similar Minerals It may be confused with other secondary, green nickel minerals, such as Gasparite-(Ce) or Ni-analogs of other antimonates. Definitive differentiation is only possible based on chemical and structural analysis. ## Crystal Forms It forms very small, hexagonal, tabular crystals, often grouped into rosette-like or irregular aggregates.

Geological environment

## Genesis It is a secondary mineral that forms in the oxidation zones of nickel deposits under specific geochemical conditions. In the type locality (Bon Accord, RSA), it occurs within serpentinized and silica-cemented ultramafic rocks that have undergone lateritic weathering processes. ## Mineral Associations It co-occurs with minerals such as quartz, trevorite, willemseite, as well as various minerals from the serpentine group and talc. ## Localities The only confirmed occurrence of Tredouxite in the world is its type locality: the Bon Accord nickel mine in the Barberton district, Mpumalanga Province, Republic of South Africa.

Rarity

Extremely rare

For collectors

## Quality Criteria The quality of Tredouxite specimens is assessed based on the richness of microcrystal clusters on the rock matrix and the intensity of their green color. The most desirable specimens are those with well-formed, though still microscopic, hexagonal crystals forming rosette-like aggregates. Due to the nature of the mineral, the purity and size of individual crystals are not key criteria. ## Popular Localities The only source of Tredouxite specimens is the Bon Accord mine in South Africa. This mineral is almost exclusively available on the specialized micromineral market.

Care and storage

## Cleaning Specimens should be handled with the utmost care. Cleaning is not recommended due to the extreme fragility and small size of the crystals. If necessary, compressed air can be used from a safe distance to remove loose dust particles. ## What to Avoid Any mechanical contact should be avoided, including ultrasonic cleaning, which could destroy the delicate crystals. Contact with acids and other chemicals should also be avoided. ## Storage Tredouxite specimens should be stored exclusively in specialized micromineral boxes (micromounts) to protect them from mechanical damage, dust, and moisture.

External references

Sources

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