Pautovite

Chemical formula: CsFe²⁺Fe³⁺S²⁻₃

Pautovite is a very rare cesium, iron(II), and iron(III) sulfide, found as small, tabular crystals with a metallic luster.

## Characteristics Pautovite is an extremely rare mineral from the sulfide group, chemically classified as a cesium and two different oxidation states of iron sulfide. It occurs in the form of very small, tabular or lamellar crystals, reaching sizes up to 0.2 x 0.1 x 0.01 mm. Its appearance is inconspicuous – it forms thin, flat flakes with a dark gray, steel-like color and a metallic luster. Due to its extreme rarity and small crystal size, it is a mineral known primarily in scientific circles. ## Physical Properties Pautovite crystals are opaque and exhibit a metallic luster. Hardness has not been precisely measured, but it is estimated to be around 2.5 on the Mohs scale, which means it is a soft mineral. Its density has also not been determined due to insufficient material for research. The streak is impossible to determine due to the small size of the grains. ## Colors and Varieties This mineral is uniform in color and occurs exclusively in a dark, steel-gray shade. No color or commercial varieties are distinguished. ## History and Name The mineral's name honors Leonid Anatolievich Pautov (born 1958), a Russian mineralogist and curator of the A.E. Fersman Mineralogical Museum in Moscow, for his contributions to the study of minerals from alkaline massifs. Pautovite was officially recognized as a new mineral species by the International Mineralogical Association (IMA) in 2004 (IMA2004-013). It was discovered and described based on material from the Palitra pegmatite within the Lovozero Massif in Russia. ## Uses Pautovite has no industrial application. Its significance is purely scientific and collectible, as a unique representative of cesium and iron sulfides.

Properties

Mohs hardness
2.5
Luster
Metallic
Streak
Could not be measured
Density
0
Cleavage
{110}
Fracture
Splintery
Transparency
Opaque
Crystal system
Orthorhombic

Diagnostic features

## Identification Identifying pautovite under amateur conditions is practically impossible. It requires advanced analytical techniques, such as X-ray microanalysis (EDS/WDS) to confirm its unique chemical composition (presence of cesium, iron, and sulfur) and X-ray diffraction (XRD) to determine its crystal structure. Visually, it can only be suspected based on its specific location (pegmatites of the Lovozero Massif) and mode of occurrence – as small, steel-gray flakes with a metallic luster. ## Distinguishing from Similar Minerals Due to its appearance, it can be confused with other small, metallic-luster sulfides, such as molybdenite, graphite, or other rare sulfides found in alkaline massifs. Certain differentiation is possible only based on chemical analysis. ## Crystal Forms Pautovite forms very small, thin, tabular or lamellar crystals, often elongated. These crystals occur individually or form small, loose aggregates on the surface of other minerals.

Geological environment

## Genesis Pautovite is a hydrothermal mineral associated with highly differentiated, alkaline nepheline-sodalite pegmatites. It forms in the late stages of crystallization of these pegmatites, under conditions of low temperature and high activity of rare elements, such as cesium. ## Mineral Associations This mineral occurs in association with other rare minerals typical of the Lovozero Massif pegmatites. At the type locality (Palitra pegmatite), it was found in association with sodalite, aegirine, ussingite, chkalovite, lomonosovite, sphalerite, galena, and two other rare cesium sulfides: rasvumite and djerfisherite. ## Localities The only confirmed and described occurrence of pautovite in the world is its type locality: the "Palitra" pegmatite in the Karnasurt mine, on Mount Karnasurt, within the alkaline Lovozero Massif, Murmansk Oblast, Russia.

Rarity

Extremely rare

For collectors

## Quality Criteria The quality of a pautovite specimen is determined almost exclusively by its clarity and richness. Since the crystals are microscopic, the most desirable specimens are those where well-formed, undamaged flakes are visible, preferably forming a small aggregate. Contrast with the matrix mineral (e.g., bright sodalite) also enhances visual value. The size of individual crystals, even if we are talking about fractions of a millimeter, is a key factor. ## Popular Localities The only source of pautovite specimens is its type locality in Russia – the Palitra pegmatite in the Lovozero Massif. All specimens available on the collector's market come from this single, historical find.

Care and storage

## Cleaning Due to its extreme rarity, small size, and potential instability, pautovite specimens, usually embedded in matrix rock, should not be cleaned mechanically or chemically. Any attempts at cleaning may irreversibly destroy the microscopic crystals. Only very careful dust removal with a soft brush or a photographic air blower is permissible. ## What to Avoid Avoid contact with water, acids, bases, and all chemical agents. As a sulfide, pautovite may be susceptible to oxidation, especially in a humid environment, which can lead to its decomposition. It should be protected from moisture, high temperatures, and direct sunlight. ## Storage Pautovite specimens must be stored under stable conditions. The best solution is a sealed, closed "micromount" box away from sources of moisture and contamination. Display should only take place in closed display cases, away from direct lighting.

External references

Sources

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