Zhanghuifenite
Chemical formula: Na₃Mn²⁺₄Mg₂Al(PO₄)₆
Zhanghuifenite is a very rare sodium, manganese, magnesium, and aluminum phosphate, forming small, platy, brown crystals.
Properties
- Mohs hardness
- 5
- Color
- deep green
- Luster
- Vitreous
- Streak
- pale green
- Density
- 3.63
- Cleavage
- good on {010}
- Fracture
- Uneven
- Transparency
- Transparent
- Crystal system
- Monoclinic
Diagnostic features
## Identification Identification of zhanghuifenite is impossible without advanced laboratory techniques. It requires chemical analysis (EDS) to confirm the presence of sodium, manganese, magnesium, aluminum, and phosphorus, and X-ray diffraction (XRD) methods to determine the crystal structure. Visually, under high magnification, characteristic, small, brown crystals with a platy habit can be observed. ## Distinguishing from Similar Minerals It can be confused with other minerals from the alluaudite group, such as alluaudite, ferroalluaudite, or manganoanalluaudite. Differentiation relies solely on precise chemical composition analysis, as all these minerals have very similar physical properties and appearance. ## Crystal Forms Crystals are very small, with a platy or bladed habit, flattened parallel to the {100} plane. They form radial aggregates or disordered clusters on the surface of the host rock.
Geological environment
## Genesis Zhanghuifenite is a hydrothermal mineral. It formed in the late stage of crystallization in granitic pegmatites, as a result of hydrothermal solutions interacting with earlier phosphate minerals, such as beryllonite. ## Mineral Associations This mineral coexists with quartz, microcline, albite, muscovite, beryllonite, eucryptite, wardite, and hydroxylapatite. ## Localities The only known occurrence of zhanghuifenite in the world is its type locality - a granitic pegmatite in Nanping (Yanping area), Nanping Prefecture, Fujian Province, China.
Rarity
Extremely rare
For collectors
## Quality Criteria As a micromineral, the collector's value of zhanghuifenite depends on the richness of the aggregates, the size (though still microscopic), and the development of individual crystals. Specimens with well-defined, radial aggregates on a contrasting background (e.g., on quartz) are most desirable. Association with other rare phosphates is also important. ## Popular Localities The only source of specimens is the type locality in Nanping, China, which means all specimens available on the market originate from there.
Care and storage
## Cleaning Specimens of zhanghuifenite, due to their microscopic nature and fragility, should not be cleaned mechanically or chemically. The safest method is to remove dust using compressed air from a safe distance. ## What to Avoid Contact with all chemicals, especially acids, which can damage the mineral, should be avoided. Ultrasonic cleaning, steam cleaning, and sudden temperature changes should also be avoided. The specimen should be protected from moisture. ## Storage Store in stable room conditions, away from direct sunlight, dust, and moisture. The best solution is to store it in a dedicated "micromount" box, which protects delicate crystals from mechanical damage.