Nolzeite

Chemical formula: Na(Mn²⁺,◻)₂[Si₃(B,Si)O₉(OH)₂](H₂O)₂

Nolzeite is a very rare, hydrated borosilicate of sodium and manganese, forming microscopic, prismatic, brown crystals.

## Characteristics Nolzeite is a mineral from the turingite group, occurring as extremely small, prismatic or acicular crystals, rarely exceeding 0.2 mm in length. It typically forms radial or tangled aggregates. The crystals are light brown to reddish-brown and exhibit distinct pleochroism in shades of brown and yellow. ## Physical Properties Nolzeite crystals have 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 2.95 g/cm³. ## Colors and Varieties This mineral occurs in shades of brown, from light to reddish-brown. No varieties have been distinguished. ## History and Name Nolzeite was recognized as a new mineral by the International Mineralogical Association (IMA) in 2011 (IMA2011-085). Its name honors the German amateur mineralogist Horst Nolze for his contribution to the development of software for precession electron diffraction (PED) analysis, which was crucial in determining the mineral's structure. It was discovered in the dumps of the Wessels Mine in South Africa. ## Applications Nolzeite has no commercial or industrial applications. It is solely an object of scientific and collecting interest for specialists who collect "microminerals."

Properties

Color
Colourless to pale green
Luster
Vitreous
Streak
White
Density
2.79
Cleavage
Good on {100} and {010}
Fracture
Uneven
Transparency
Transparent to translucent
Crystal system
Triclinic

Diagnostic features

## Identification Identification of nolzeite is impossible without advanced analytical methods. It requires chemical analysis (EDS) and diffraction methods (XRD, PED) to confirm its composition and structure. Visually, at the occurrence site, it can be suspected based on its brown color, acicular crystal form, and co-occurrence with other rare manganese minerals. ## Distinguishing from Similar Minerals It can be confused with other acicular manganese minerals, such as some pyroxenes, amphiboles, or other silicates from the turingite group. Definitive differentiation is only possible through laboratory analysis. ## Crystal Forms It forms elongated, prismatic or acicular crystals, often grouped into radial or chaotic aggregates. The crystals exhibit a cross-section close to square.

Geological environment

## Genesis Nolzeite is a hydrothermal mineral, formed at low temperatures. It forms in fissures and vugs within manganese ore deposits that have undergone contact metamorphism. ## Mineral Associations At the type locality (Wessels Mine), it co-occurs with minerals such as sugilite, henritermierite, braunite, and hematite. ## Localities The only confirmed locality for nolzeite in the world is the Wessels Mine, located in the Kalahari Manganese Field in the Northern Cape Province, Republic of South Africa.

Rarity

Extremely rare

For collectors

## Quality Criteria As a micromineral, nolzeite is primarily evaluated based on the richness and aesthetics of crystal aggregates on the rock matrix. Specimens with clearly formed, undamaged crystals forming visually attractive groups, preferably in association with other rare minerals, are most desirable. The color and size of the crystals (though always microscopic) are also important. ## Popular Localities The only source of specimens is the Wessels Mine in South Africa, which is known for supplying many rare and unique manganese minerals.

Care and storage

## Cleaning Nolzeite specimens are extremely delicate and small. Mechanical or chemical cleaning is not recommended. If absolutely necessary, compressed air can be used from a safe distance to remove loose dust particles. ## What to Avoid Avoid contact with all chemicals, ultrasound, and sudden temperature changes. The crystals are brittle and easily susceptible to mechanical damage. ## Storage Specimens should be stored exclusively in specialized micromount boxes to protect them from dust, shocks, and mechanical damage. They require viewing under a microscope.

External references

Sources

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