Diegogattaite

Chemical formula: Na<sub>2</sub>CaCu<sup>2+</sup><sub>2</sub>Si<sub>8</sub>O<sub>20</sub>·H<sub>2</sub>O

Diegogattaite is a very rare copper, calcium, and sodium silicate, forming characteristic blue, fibrous or bladed crystals.

## Characteristics Diegogattaite is a hydrated copper, calcium, and sodium silicate, belonging to the group of very rare minerals. It occurs as small, elongated crystals with a bladed or acicular habit, often forming tangled aggregates or radial clusters. Its most distinctive feature is its intense blue color, which makes it recognizable despite the small size of its crystals. ## Physical Properties Diegogattaite crystals are flexible and have a hardness of approximately 4 on the Mohs scale. The mineral's luster is described as vitreous, and its crystals are typically transparent to translucent. The calculated density is 2.89 g/cm³. ## Colors and Varieties This mineral occurs in a uniform, light blue color. No color varieties or commercial forms are known. ## History and Name Diegogattaite was discovered in a quarry at the Wessels Mine, part of the Kalahari Manganese Field in the Republic of South Africa. It was approved as a new mineral by the International Mineralogical Association (IMA) in 2011. Its name honors Dr. Diego Gatta (born 1975), an Italian mineralogist and crystallographer from the University of Milan, for his contributions to silicate research. ## Applications Due to its extreme rarity and small crystal size, diegogattaite has no industrial applications. It is solely an object of interest for collectors specializing in rare minerals and for scientists.

Properties

Mohs hardness
4
Luster
Vitreous
Streak
Light blue
Density
2.89
Cleavage
Perfect on {100}
Fracture
Uneven
Transparency
Transparent to translucent
Crystal system
Monoclinic

Diagnostic features

## Identification Diegogattaite can be identified by its characteristic light blue color, vitreous luster, and mode of occurrence – it forms aggregates composed of small, bladed or fibrous crystals. The locality is also crucial – it originates from one specific place in the world. ## Distinguishing from Similar Minerals It can be confused with other blue, secondary copper minerals such as shattuckite, planchéite, or chrysocolla. Differentiation requires advanced analytical methods, such as chemical analysis (EDS) or X-ray diffraction (XRD). For collectors, verification of the specimen's provenance is fundamental. ## Crystal Forms It forms elongated, bladed crystals, up to 1 mm long, which often occur as radial or tangled aggregates. The crystals are flexible.

Geological environment

## Genesis Diegogattaite is a hydrothermal mineral. It formed during a late stage of mineralization within a manganese deposit, crystallizing in small voids and rock fractures. Its formation is associated with the circulation of solutions rich in copper, calcium, and sodium within the host rocks. ## Mineral Associations This mineral occurs in association with other rare minerals, such as sugilite, pectolite, quartz, scottyite, wesselsite, and richterite. Co-occurrence with these minerals is an important diagnostic clue. ## Localities The only confirmed occurrence of diegogattaite worldwide is its type locality – the Wessels Mine in Hotazel, within the Kalahari Manganese Field (Northern Cape Province, South Africa).

Rarity

Extremely rare

For collectors

## Quality Criteria The most highly valued diegogattaite specimens are those that possess well-formed, rich clusters of intensely blue crystals, contrasting with a light matrix rock (most often with pectolite). The size of the aggregates and the intensity of the color are key factors influencing value. Due to its rarity, even microscopic specimens are sought after. ## Popular Localities The only source of specimens is the Wessels Mine in South Africa. Material from this locality is extremely rarely available on the collector's market.

Care and storage

## Cleaning Specimens should be cleaned very carefully, using only a soft brush to remove dust. Due to its delicacy and potential reactivity, contact with water and any chemical agents should be avoided. ## What to Avoid Ultrasonic cleaners, strong cleaning agents, acids, and solvents must be strictly avoided. The mineral is sensitive to shocks and impacts, which can damage delicate crystals. It should be protected from high temperatures and humidity. ## Storage It is recommended to store specimens in stable conditions, in a closed display box, away from dust, sunlight, and sudden temperature changes. It is best to keep it in its original locality box to avoid mechanical damage.

Sources

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