Epiebnerite
Chemical formula: (N³⁻H₄)Zn²⁺(PO₄)
Epiebnerite is a newly discovered, extremely rare zinc ammonium phosphate, found as a product of human activity in the Austrian Alps.
Properties
- Mohs hardness
- 2-0
- Color
- colorless
- Luster
- Vitreous
- Streak
- white
- Density
- 2.851
- Transparency
- Transparent
- Crystal system
- Monoclinic
Diagnostic features
## Identification Identification of epiebnerite is possible only through advanced analytical methods, such as Raman spectroscopy or X-ray diffraction (XRD), due to the microscopic size of the crystals. It is visually unidentifiable. ## Distinguishing from similar minerals It can be confused with other secondary, microcrystalline phosphates or sulfates formed in similar environments. Key to distinguishing it is the determination of the presence of zinc and the ammonium group in its chemical composition, which requires specialized equipment. ## Crystal forms It forms very small, thin, tabular crystals, often arranged in rosette-like or chaotic aggregates and thin crusts on the host rock.
Geological environment
## Genesis Epiebnerite is a mineral of anthropogenic and biogenic genesis. It formed as a result of the reaction between acidic waters percolating through a dump of post-smelting waste (containing sphalerite) and guano (droppings) from sheep that sheltered in an old adit. It is a product of weathering in a very specific, human-made microenvironment. ## Mineral associations It co-occurs with other rare secondary minerals, such as gunningite, nishimotoite, salmoite, spencerite, as well as gypsum and quartz. ## Localities The only known occurrence in the world (type locality) is the dump of the former smelter in Kolm-Saigurn, in the Rauris Valley, in the Hohe Tauern (Salzburg, Austria).
Rarity
Extremely rare
For collectors
## Quality criteria As a microscopic mineral, the quality of a specimen is determined by the richness and aesthetics of the crystal aggregates visible under magnification. The most valuable samples are those with clearly visible, though tiny, epiebnerite crusts, ideally in association with other rare minerals from this locality. Analytical confirmation (e.g., by Raman spectroscopy) significantly increases the value of the specimen. ## Popular localities The only source of specimens is the type locality in Austria. Material from this location is extremely limited and available almost exclusively in specialized circles among micromount collectors.
Care and storage
## Cleaning Epiebnerite specimens are extremely delicate and microscopic. They should not be cleaned mechanically or chemically. Any attempts at cleaning may irreversibly destroy the mineral. ## What to avoid Avoid contact with water, chemicals, as well as any vibrations and shocks. Due to its genesis, it may be unstable under varying humidity and temperature conditions. ## Storage Specimens should be stored exclusively in specialized, sealed "micromount" boxes, protecting them from dust, moisture, and mechanical damage. Handle them with the utmost care.