Cabalzarite

Chemical formula: CaMg₂(As⁵⁺O₄)₂·₂H₂O

Cabalcazarite is a rare, pinkish-red calcium and magnesium arsenate, forming small, vitreous crystals in manganese deposits.

## Characteristics Cabalcazarite is a hydrated calcium and magnesium arsenate belonging to the roselite group. It occurs as very small, tabular or bladed crystals, rarely exceeding 1 mm in length. These crystals form rosette-like or radial aggregates, as well as thin crusts on rock surfaces. Due to the small size of the crystals, its macroscopic features are difficult to observe with the naked eye. ## Physical Properties Cabalcazarite crystals exhibit a vitreous luster and are transparent to translucent. Its Mohs hardness is approximately 3.5, and its density is approximately 3.45 g/cm³. This mineral is brittle. ## Colors and Varieties Cabalcazarite is characterized by an intense, pinkish-red to red color. No color or commercial varieties are known. ## History and Name The mineral was discovered in Alpine manganese deposits in the Falotta valley, Grisons canton, Switzerland. It was described in 1998 by Joël Brugger, Stefan Graeser, Nicolas Meisser, and Peter Berlepsch. The name "cabalcazarite" honors Walter Cabalzar-Solèr (1919-2007), a Swiss mineral collector who found the first samples of this mineral. ## Applications Cabalcazarite has no industrial applications. It is solely a mineral of scientific and collector interest, sought after by specialized collectors of rare minerals (so-called micromounts).

Properties

Mohs hardness: 5
Color: Light brownish to salmon-pink or orange-brown.
Luster: Vitreous
Streak: White
Density: 3.89
Cleavage: Perfect on {010}
Fracture: Irregular/Uneven
Transparency: Transparent
Crystal system: Monoclinic

Diagnostic features

## Identification Characteristic features of cabalcazarite include its intense pinkish-red color, occurrence as small, tabular crystals forming rosette-like aggregates, and its specific geological environment. Reaction with hydrochloric acid (rapid dissolution) is a strong diagnostic indicator, but it destroys the sample. ## Distinguishing from Similar Minerals Cabalcazarite can be confused with other pink or red arsenates from the roselite group, such as roselite or brandtite. Roselite has a similar color but crystallizes in the monoclinic system and has a different chemical composition (containing cobalt instead of magnesium). Brandtite is also similar but contains manganese. Final differentiation of these minerals requires advanced chemical analyses (EDS) or X-ray diffraction (XRD). ## Crystal Forms Crystals are very small, usually tabular or bladed, flattened. They often form fan-shaped, radial, or rosette-like clusters and aggregates. They also occur as thin coatings and crusts on the host rock.

Geological environment

## Genesis Cabalcazarite is a secondary mineral, formed by hydrothermal or metamorphic processes within manganese and iron ore deposits. It forms in rock fractures and cavities, crystallizing from solutions rich in arsenic, calcium, and magnesium. ## Mineral Associations This mineral co-occurs with other rare manganese minerals and arsenates. In its type locality (Falotta, Switzerland), it was found in association with brandtite, sarkinite, berzeliite, ekdemite, as well as quartz, barite, and calcite. ## Localities The most important and type locality for cabalcazarite is the Falotta valley in the Oberhalbstein (Surses) region of the Grisons canton, Switzerland. This is the only confirmed and well-documented locality for this mineral worldwide.

Rarity

Very rare

For collectors

## Quality Criteria The quality of cabalcazarite specimens is primarily assessed based on the richness and aesthetics of the crystal aggregates. Samples with clearly formed, undamaged rosettes or fans of crystals with an intense, pinkish-red color are most valued. Contrast with the rock matrix and the presence of rare associated minerals are also important. ## Popular Localities The only source of collector specimens is its type locality – the Falotta valley in Switzerland. Specimens from this location are highly sought after by collectors specializing in Alpine minerals and rare species (so-called "systematists").

Care and storage

## Cleaning Specimens should be cleaned only very carefully, using a soft brush to remove dust. Due to its solubility in acids, contact with water, especially demineralized water, should be as brief as possible. Dry cleaning is the safest method. ## What to Avoid Contact with acids (including hydrochloric acid), which rapidly dissolve it, must be absolutely avoided. It should be protected from high temperatures, which can cause the loss of water from its structure. Avoid ultrasonic cleaners and hard brushes, which can damage delicate crystals. ## Storage Cabalcazarite specimens, typically as micromounts, should be stored in sealed, transparent boxes (perky boxes) that protect them from dust, moisture, and mechanical damage. Avoid exposure to direct sunlight and extreme temperature fluctuations.