Ebnerite

Chemical formula: (N³⁻H₄)Zn²⁺(PO₄)

Ebnerite is a hydrated zinc ammonium phosphate, forming microscopic, colorless crystals in caves with bat guano.

## Characteristics Ebnerite is a rare mineral from the phosphate group, chemically classified as a hydrated zinc ammonium phosphate. It occurs as very small, colorless or white tabular or bladed crystals. These crystals are typically so fine that a microscope is essential for their observation. It forms coatings and crusts on rocks or other minerals in the specific environment of guano-rich caves. ## Physical Properties Ebnerite crystals exhibit a vitreous luster. Due to the microscopic size of the crystals, determining many physical properties, such as hardness or density, is impossible or very difficult. The mineral is transparent. ## Colors and Varieties Ebnerite is typically colorless to white. No colored or commercial varieties are distinguished. ## History and Name The mineral was named after Franz Ebner (born 1952), an Austrian geologist and stratigraphy specialist from the University of Leoben. Ebner made significant contributions to the geological research of the Eastern Alps. Ebnerite was approved as a new mineral species by the International Mineralogical Association (IMA) in 2013. ## Uses Ebnerite has no industrial application. Its significance is purely scientific and collectible, although due to its rarity and microscopic nature, it is primarily of interest to specialized collectors of rare minerals (so-called micromounts).

Properties

Mohs hardness
2-0
Color
colorless
Luster
Vitreous
Streak
white
Density
2.78
Cleavage
one good cleavage in the [001] zone – possibly {100}.
Fracture
Splintery
Transparency
Transparent
Crystal system
Hexagonal

Diagnostic features

## Identification Identification of ebnerite is possible almost exclusively through advanced analytical methods, such as X-ray diffraction (XRD) or Raman spectroscopy. Visually, at the occurrence site, it can be suspected in white, crystalline crusts co-occurring with other struvite-group phosphates in guano caves. ## Distinguishing from Similar Minerals Ebnerite is visually indistinguishable from many other secondary phosphate minerals forming microscopic crystals, such as newberyite, hannayite, or schertelite. Definitive differentiation requires specialized laboratory tests. ## Crystal Forms It forms very small, tabular or bladed crystals, often grouped into rosetted aggregates or forming thin crusts and coatings.

Geological environment

## Genesis Ebnerite is a secondary mineral. It forms as a result of reactions between phosphate and ammonia-rich solutions, derived from the decomposition of bat guano, and zinc minerals present in the surrounding rocks (e.g., in sphalerite-bearing dolomites). ## Mineral Associations This mineral co-occurs with other phosphates and sulfates formed under similar conditions, such as gypsum, brushite, newberyite, hannayite, schertelite, and sphalerite. ## Localities The only known locality for ebnerite in the world (type locality) is the Schurfhöhle cave in the Kugelstein massif, near the town of Peggau in Styria, Austria.

Rarity

Extremely rare

For collectors

## Quality Criteria As a microscopic mineral, ebnerite is primarily valued by collectors specializing in micromounts. The value of a specimen is determined by the abundance and good crystallization of crystals visible under the microscope, as well as their association with other rare minerals. The size of the host rock specimen itself is of secondary importance. ## Popular Localities The only source of ebnerite specimens is its type locality in Austria.

Care and storage

## Cleaning Specimens containing ebnerite should generally not be wet-cleaned. The mineral is potentially water-soluble. A soft brush or a photographic air blower can be used to remove dust. ## What to Avoid Absolute avoidance of contact with water, acids, and other chemicals is essential. Store away from moisture, as this can lead to the decomposition of the mineral. It should not be heated. ## Storage Ebnerite specimens, typically in the form of micromounts, should be stored in sealed, lockable boxes (micromount boxes) to protect them from dust, moisture, and mechanical damage. It is recommended to add a desiccant to the container.

External references

Sources

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