Catalanoite

Chemical formula: Na<sub>2</sub>HPO<sub>4</sub>·8H<sub>2</sub>O

Catalanoite is a hydrated sodium phosphate that forms colorless, tabular crystals in lake sediments.

## Characteristics Catalanoite is a hydrated sodium phosphate, occurring as fine, colorless crystals with a tabular habit. It typically forms rosette-like or spherical aggregates, reaching up to 0.5 mm in diameter. It is an unstable mineral under atmospheric conditions – it rapidly loses water (dehydrates), leading to its disintegration and loss of transparency. ## Physical Properties Catalanoite crystals are very soft and brittle. They exhibit a vitreous luster and are transparent. Due to its instability, precise determination of physical properties such as hardness and density is difficult. ## History and Name The mineral was approved by the IMA in 2007. Its name honors Professor Gustavo Catalano (born 1942), an Argentine chemist and crystallographer from the National University of Rosario, for his contributions to the study of phosphates and arsenates. The discovery was made in samples from the sediments of Laguna de Pozuelos lake in Argentina. ## Uses Catalanoite has no industrial applications. Its significance is purely scientific and as a collector's item, although its instability makes it extremely difficult to preserve in collections.

Properties

Luster
Vitreous
Streak
White
Density
1.62
Cleavage
Perfect on {010}
Transparency
Transparent
Crystal system
Triclinic

Diagnostic features

## Identification Identification of catalanoite is primarily based on its specific occurrence environment (evaporites of alkaline lakes) and its instability under atmospheric conditions. Characteristic features include small, colorless, tabular crystals forming rosette-like aggregates that quickly become opaque and disintegrate after removal from their natural environment. ## Differentiation from Similar Minerals It can be confused with other hydrated phosphates or sulfates found in similar environments, such as nahpoite (Na₂HPO₄) or mirabilite (Na₂SO₄·10H₂O). Catalanoite is distinguished by its specific chemical composition (containing 8 water molecules) and crystal habit. Final identification requires X-ray diffraction (XRD) analysis. ## Crystal Forms It forms thin, tabular, bladed crystals, often grouped into rosettes or spherical aggregates.

Geological environment

## Genesis Catalanoite is an evaporite mineral, crystallizing at low temperatures (below 5°C) from highly saline and alkaline lake waters, rich in phosphates and sodium. It forms in bottom sediments during the winter period. ## Mineral Associations It co-occurs with other evaporite minerals, such as halite (NaCl), trona (Na₃(CO₃)(HCO₃)·2H₂O), thermonatrite (Na₂CO₃·H₂O), and nahpoite (Na₂HPO₄). ## Localities The only confirmed occurrence (type locality) is Laguna de Pozuelos, a salt lake in Jujuy Province, Argentina.

Rarity

Extremely rare

For collectors

## Quality Criteria Due to its extreme rarity and instability, any well-formed and as well-preserved specimen as possible is scientifically valuable. Its collector's value is limited by storage difficulties. The most desirable would be clear, transparent crystals in rosette form, secured in their original medium or in oil.

Care and storage

## Cleaning Catalanoite specimens should not be cleaned. Any contact with water, alcohol, or other liquids will cause it to dissolve. Mechanical cleaning, even with a soft brush, should be avoided due to its extreme brittleness. ## What to Avoid Contact with water and moisture must be strictly avoided. The mineral is very sensitive to changes in temperature and air humidity. Even at room temperature and low humidity, it rapidly loses water, leading to its disintegration. It must not be exposed to sunlight or heated. ## Storage The only effective storage methods are to keep the specimen in an hermetically sealed container, preferably immersed in paraffin oil or another anhydrous medium, to prevent dehydration. Alternatively, it can be stored under refrigerated conditions, in an atmosphere with controlled, high humidity.

Sources

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