Fianelite

Chemical formula: Mn²⁺₂V⁵⁺₂O₇·₂H₂O

Fianelite is a rare, hydrated manganese vanadate, forming microscopic, tabular crystals of intense red color and vitreous luster.

## Characteristics Fianelite is a hydrated manganese vanadate, occurring as very small, tabular or bladed crystals, rarely exceeding 0.2 mm in length. These crystals often form rosette-like or radial aggregates. A characteristic feature of the mineral is its intense, red to reddish-orange color. ## Physical Properties Fianelite crystals exhibit a vitreous luster. They are transparent to translucent. The Mohs hardness is approximately 2.5, classifying it as a soft mineral. The density calculated from the formula and cell parameters is 3.25 g/cm³. ## Colors and Varieties This mineral occurs in uniform, vivid shades of red and reddish-orange. No varieties have been distinguished. ## History and Name Fianelite was discovered in the Fianel mine in the Ferrera Valley, in the canton of Graubünden, Switzerland. It was described and approved as a new mineral species by the International Mineralogical Association (IMA) in 1996. Its name comes directly from its type locality – the Fianel mine.

Properties

Mohs hardness: 3
Color: Red-orange
Luster: Vitreous , Adamantine
Streak: orange
Density: 3.21
Cleavage: Parallel {001}(?) and {100}(?), good.
Fracture: Uneven
Transparency: Transparent
Crystal system: Monoclinic

Diagnostic features

## Identification Fianelite can be identified by its characteristic, intense red color, tabular form of microscopic crystals, and occurrence in association with other manganese minerals in metamorphic deposits. ## Distinguishing from Similar Minerals It can be confused with other red vanadates, such as hewettite or pascoite, but differs from them in crystal habit and specific geological environment. Final differentiation requires advanced analytical methods, such as X-ray diffraction (XRD) or chemical analysis (EDS). ## Crystal Forms It forms very small, thin, tabular crystals with a hexagonal or rhombic outline. These crystals often combine into small, radial or rosette-like aggregates.

Geological environment

## Genesis Fianelite is a secondary mineral, formed as a result of hydrothermal or metamorphic processes in manganese and iron ore deposits rich in vanadium. It forms in fractures and small rock cavities. ## Mineral Associations It most commonly co-occurs with minerals such as braunite, piemontite, rhodonite, saneroite, palenzonaite, medaite, and quartz. ## Localities The only confirmed and described locality of fianelite in the world is its type locality – the Fianel mine in the Ferrera Valley, in the Viamala region, in the canton of Graubünden, Switzerland.

Rarity

Extremely rare

For collectors

## Quality Criteria As a "micromount" type mineral, the quality of a specimen is primarily determined by the richness and development of crystals within the microscope's field of view. The most valued are aggregates of well-formed, intensely red crystals, clearly standing out from the matrix rock. The size of individual crystals, even if it is a fraction of a millimeter, also increases the value of the specimen. ## Popular Localities The only source of fianelite specimens is the Fianel mine in Switzerland, which makes every specimen from this locality highly sought after by specialized collectors of rare and micromount minerals.

Care and storage

## Cleaning Fianelite specimens, due to their extreme rarity and small size, practically do not require cleaning. If absolutely necessary, only compressed air should be used to remove dust. Any contact with water or other liquids should be avoided. ## What to Avoid Contact with water, chemicals, acids, and detergents must be strictly avoided. As a soft mineral, it is very susceptible to mechanical damage. It should be protected from high temperatures and direct sunlight, which can cause dehydration and destruction. ## Storage Fianelite specimens should be stored in stable conditions, in closed, padded "micromount" boxes that protect them from dust, moisture, and physical damage. Store away from heat and light sources.