Alumovesuvianite

Chemical formula: Ca₁₉Al(Al₁₀Mg₂)Si₁₈O₆₉(OH)₉

Alumovesuvianite is a rare mineral of the vesuvianite group, characterized by high aluminum content and a reddish-brown color.

## Characteristics Alumovesuvianite is a complex calcium, aluminum, and magnesium silicate, belonging to the vesuvianite group. Its name refers to the dominance of aluminum in its chemical composition and its structural relationship with vesuvianite. Typical specimens form short, prismatic crystals with a square cross-section or granular and massive aggregates. It is a hard and relatively dense mineral. ## Physical Properties The hardness of alumovesuvianite on the Mohs scale is approximately 6.5, which is typical for minerals of its group. It has a vitreous luster, is often translucent, and opaque in larger masses. Its density is approximately 3.41 g/cm³. ## Colors and Varieties This mineral is characterized by a uniform, reddish-brown or brownish-red color. Due to its rarity, no color or commercial varieties have been identified to date. ## History and Name Alumovesuvianite was officially recognized as a new mineral species by the International Mineralogical Association (IMA) in 2016. Its name comes from its high aluminum content (Latin: *alumen*) and its similarity to vesuvianite. The type locality, from which the first described specimens originated, is the Lupikko skarn deposit in Pitkyaranta, Karelia, Russia. ## Applications Due to its rarity and small accumulations, alumovesuvianite has no industrial applications. It is solely an object of scientific interest and a prized acquisition for advanced collections of systematic and regional minerals.

Properties

Mohs hardness: 6.5
Luster: Vitreous
Streak: White
Density: 3.41
Cleavage: Poor
Fracture: Uneven
Transparency: Translucent
Crystal system: Tetragonal

Diagnostic features

## Identification Field identification of alumovesuvianite is difficult due to its resemblance to other minerals of the vesuvianite group and some garnets. Key features include its reddish-brown color, tetragonal crystal habit (if visible), and occurrence in a specific geological environment (skarns). Definitive identification requires advanced chemical (EDS) and structural (XRD) analyses. ## Distinguishing from Similar Minerals Alumovesuvianite can be confused with more common vesuvianite, which, however, rarely has such a high aluminum content and occurs in a wider range of colors (often green and brown). From reddish-brown garnets (e.g., andradite), it is distinguished by a different, tetragonal crystallographic system (garnets crystallize in the isometric system) and usually less well-developed crystal faces. ## Crystal Forms Alumovesuvianite forms short, prismatic crystals with a columnar habit, often terminated by flat pinacoid faces. It also occurs as granular aggregates or compact, massive aggregates intergrown with rock.

Geological environment

## Genesis This mineral forms under conditions of contact metamorphism, within calc-silicate skarns. Its crystallization is a result of metasomatic processes occurring at the contact between granitoid intrusions and carbonate rocks (limestones or dolomites). ## Mineral Associations Alumovesuvianite coexists with other minerals typical of the skarn environment. Its most common associations include wollastonite, garnets of the grossular-andradite series, diopside, fluorapophyllite, fluorite, and calcite. ## Localities The most important and, to date, the only well-documented locality for high-quality alumovesuvianite is its type locality – the inactive Lupikko mine in the Pitkyaranta region of the Republic of Karelia, Russia.

Rarity

Very rare

For collectors

## Quality Criteria The most highly valued by collectors are specimens with well-formed, lustrous crystals of intense, reddish-brown color. An additional advantage is their aesthetic placement on a light matrix, for example, accompanied by white wollastonite or greenish diopside. The size of the crystals and the absence of mechanical damage also significantly increase the value of the specimen. ## Popular Localities The only source of collector's specimens is the historical type locality in Karelia, Russia. Material from this location is very limited and sought after by specialized collectors of rare minerals.

Care and storage

## Cleaning Alumovesuvianite specimens can be cleaned with a soft brush under lukewarm running water or, for delicate specimens on matrix, using distilled water and tweezers to remove impurities. Ultrasonic cleaners are not recommended, as they can cause internal fractures in the crystals. ## What to Avoid The mineral is sensitive to strong acids. Avoid sudden temperature changes. Despite its significant hardness, brittle crystals can be mechanically damaged if handled carelessly. ## Storage Collector's specimens of alumovesuvianite are best stored in separate, padded boxes or display cases to prevent scratching by harder minerals and abrasion from other specimens. They should be protected from dust and prolonged exposure to direct sunlight.

Sources

IMA Mineral List (CNMNC)