Mangani-dellaventuraite

Chemical formula: NaNa₂(MgMn³⁺₂LiTi⁴⁺)Si₈O₂₂O₂

A rare amphibole from the dellaventuraite group, distinguished by its pinkish-red color imparted by manganese and titanium in its structure.

## Characteristics Mangani-dellaventuraite is a very rare mineral belonging to the amphibole group. It is a silicate with a complex chemical composition, containing sodium, magnesium, manganese, lithium, and titanium. It forms elongated, prismatic crystals that typically occur as radial or fibrous aggregates. Its most characteristic feature is an intense, pink to red color. ## Physical Properties This mineral has a hardness of 5 on the Mohs scale. The crystals are transparent and exhibit a vitreous luster. The fracture is conchoidal. It possesses distinct cleavage in two directions, intersecting at an angle of approximately 56 degrees, which is typical for amphiboles. ## Colors and Varieties Observed colors range from pink to red. The intensity of the color depends on the content of manganese (Mn³⁺) and titanium (Ti⁴⁺) in the crystal structure. No separate commercial or color varieties of this mineral have been distinguished. ## History and Name The mineral's name refers to its chemical composition – the "Mangani" prefix indicates the dominance of manganese at a specific structural site. The second part, "dellaventuraite", honors Giancarlo Dellaventura, an Italian mineralogist and professor at Sapienza University of Rome, for his contributions to amphibole research. The mineral was officially recognized by the International Mineralogical Association (IMA) in 2015. The type locality (locus typicus) is the Kajlidongri mine in India. ## Uses Mangani-dellaventuraite has no industrial applications. Its significance is purely scientific and collectible due to its extreme rarity and unique chemical composition.

Properties

Mohs hardness
5
Luster
Vitreous
Streak
Pale pink
Density
0
Cleavage
{110}. Cleavage intersecting at ~56°.
Fracture
Conchoidal
Transparency
Transparent
Crystal system
Monoclinic

Diagnostic features

## Identification Diagnostic features include: pinkish-red color, prismatic crystal habit, occurrence in radial aggregates, and amphibole-typical cleavage. A pale pink streak is also helpful for identification. However, final confirmation requires advanced chemical (EDS/WDS) and crystallographic (XRD) analyses. ## Distinguishing from Similar Minerals This mineral can be confused with other pink silicates, such as rhodonite or rhodochrosite. However, rhodonite is significantly harder (5.5-6.5) and crystallizes in the triclinic system. Rhodochrosite (hardness 3.5-4) exhibits perfect rhombohedral cleavage and reacts strongly with acids. It is distinguished from other amphiboles by its unique combination of color and chemical composition. ## Crystal Forms Mangani-dellaventuraite forms elongated, columnar, or acicular crystals. It is most commonly found as radial or fibrous clusters and aggregates, embedded in the host rock.

Geological environment

## Genesis This is a metamorphic mineral. It forms in manganese deposits that have undergone metamorphism under amphibolite facies conditions. Its presence is associated with high sodium and oxygen activity in the formation environment. ## Mineral Associations At the type locality (Kajlidongri mine), it co-occurs with minerals such as quartz, braunite, bixbyite-(Mn), piemontite, albite, tirodite, and other sodium and calcium amphiboles. ## Localities The only confirmed and described occurrence of this mineral in the world is the Kajlidongri manganese mine, in the Jhabua district, Madhya Pradesh state, India.

Rarity

Extremely rare

For collectors

## Quality Criteria The most highly valued specimens are those with well-formed, clearly visible crystals of intense red color. Contrast with a light host rock (matrix) on which the aggregates are embedded enhances attractiveness. The size of the crystals and the entire specimen also matters, although even microscopic examples have significant scientific value. ## Popular Localities The only source of specimens of this mineral is its type locality – the Kajlidongri mine in India. Material from this location is extremely difficult to obtain on the collector's market.

Care and storage

## Cleaning Specimens should only be cleaned mechanically, using a soft brush to remove dust. If necessary, compressed air can be used. The use of water is not recommended due to the risk of damaging delicate aggregates. ## What to Avoid Avoid contact with all chemicals, especially acids, which can react with the mineral. The mineral is relatively soft, so it must be protected from scratching by harder materials. Ultrasonic cleaning devices should also be avoided. ## Storage It is recommended to store specimens in separate, padded collector's boxes to prevent abrasion and mechanical damage. They should be protected from dust and moisture. Due to its rarity, specimens should be handled with the utmost care.

External references

Sources

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