Cobaltoblödite

Chemical formula: Na₂Co²⁺(S⁶⁺O₄)₂·₄H₂O

A rare, hydrated sodium cobalt sulfate, forming characteristic, reddish-pink crystalline aggregates.

## Characteristics Cobaltoblödite is a hydrated sodium cobalt sulfate belonging to the blödite group. This mineral forms aggregates of small, tabular or prismatic crystals, which rarely exceed 1 mm in length. Most often, it occurs as granular or powdery aggregates and coatings. Its most characteristic feature is its intense, reddish-pink color, which distinguishes it in the environment where it forms. ## Physical Properties Cobaltoblödite is a relatively soft mineral, with a hardness of 2.5 on the Mohs scale, meaning it can be scratched with a fingernail. It has a density of 2.29 g/cm³, making it quite light. Crystals, if well-formed, are transparent and exhibit a vitreous luster. It is brittle, and its fracture is uneven. ## Colors and Varieties This mineral occurs in one characteristic color – reddish-pink. The intensity of the color depends on the size of the crystals and the form of aggregation. No color or commercial varieties are distinguished. ## History and Name The name cobaltoblödite refers to its chemical composition – the dominance of cobalt – and its structural similarity to the mineral blödite. It was officially recognized as a new mineral by the International Mineralogical Association (IMA) in 1998. It was described based on specimens found in the Blue Lizard mine in Utah, USA. ## Uses Due to its extreme rarity and small crystal size, cobaltoblödite has no industrial applications. It is solely an object of interest for collectors specializing in rare minerals or sulfate minerals.

Properties

Mohs hardness: 2.5
Luster: Vitreous
Streak: White
Density: 2.29
Cleavage: None
Fracture: Irregular/Uneven
Transparency: Transparent
Crystal system: Monoclinic

Diagnostic features

## Identification The key diagnostic feature of cobaltoblödite is its intense, reddish-pink color, its mode of occurrence (fine aggregates and coatings), and its geological environment. Its reaction to moisture (water solubility) is also a characteristic feature, although destructive to the sample. ## Distinguishing from Similar Minerals Cobaltoblödite can be confused with other pink, secondary cobalt minerals, such as erythrite. However, erythrite most often forms acicular or radial aggregates and crystallizes in the monoclinic system, often exhibiting perfect cleavage, which is absent in cobaltoblödite. Final differentiation requires advanced analytical methods (e.g., XRD). ## Crystal Forms Cobaltoblödite forms very small, tabular or short-prismatic crystals. It usually occurs as fine-grained aggregates, powdery coatings, or as a component of efflorescences on host rocks.

Geological environment

## Genesis Cobaltoblödite is a secondary mineral formed in the oxidation zones of deposits containing cobalt sulfides. It forms in desert and arid conditions as a result of evaporation of solutions rich in sulfates, sodium, and cobalt. It arises as a product of the weathering of primary minerals. ## Mineral Associations At the type locality (Blue Lizard Mine), it co-occurs with other sulfates, such as chalcanthite, pickeringite, epsomite, as well as gypsum and thenardite. Other secondary cobalt minerals are also associated with it. ## Localities The only confirmed and thoroughly described occurrence of cobaltoblödite in the world is its type locality – the Blue Lizard mine, in the Red Canyon district, San Juan County, Utah, USA.

Rarity

Very rare

For collectors

## Quality Criteria The most valuable cobaltoblödite specimens are those that have rich, intensely colored coatings on a small rock matrix. Due to the microscopic size of the crystals, their individual form is not a key criterion. What matters most is the abundance of the mineral on the specimen, its purity, and contrast with the surrounding rock. Specimens from a well-documented type locality are particularly prized. ## Popular Localities The only source of collector specimens is the Blue Lizard mine in Utah, USA. Material from this location is extremely rare on the market and sought after by specialized collectors.

Care and storage

## Cleaning Cobaltoblödite specimens are very delicate and water-soluble. They must absolutely not be cleaned wet. The only safe method for removing dust is to use a soft brush or carefully blow off particles with compressed air from a distance. ## What to Avoid Avoid contact with water, water vapor, and any chemicals that could dissolve or damage it. The mineral is sensitive to changes in humidity, which can lead to its dehydration or disintegration. It should be protected from high temperatures and direct sunlight. ## Storage It is recommended to store specimens in tightly sealed, dry containers (e.g., perky boxes) away from sources of moisture. It is best to keep it in stable room conditions, in a shaded place, to prevent fading and degradation.