Pauflerite

Chemical formula: V⁴⁺O(S⁶⁺O₄)

Pauflerite is a rare vanadyl sulfate, forming microscopic, platy crystals of an intense blue color.

## Characteristics Pauflerite is a hydrated vanadyl sulfate, occurring as very small, thin, platy crystals that rarely exceed 0.2 mm. It typically forms rosette-like or spherical aggregates, as well as coatings and crusts. Its most distinctive feature is its vivid blue color. ## Physical Properties Pauflerite crystals exhibit a vitreous luster. Due to the small size of the crystals, many physical properties, such as hardness or density, have not been precisely determined. The density calculated based on the formula and unit cell parameters is 3.19 g/cm³. ## Colors and Varieties Pauflerite is a mineral with one characteristic color – blue to greenish-blue. No varieties are distinguished. ## History and Name The mineral was approved by the IMA in 2017. Its name honors Robert Paufler, a mineral collector from Tulsa, Oklahoma (USA), who first noticed and collected samples of this mineral. It was described by Anthony R. Kampf, Joe Marty, John M. Hughes, and Timothy P. Rose. ## Uses Pauflerite, due to its rarity and microscopic size, has no industrial applications. It is solely an object of interest for collectors specializing in rare minerals or vanadium minerals.

Properties

Mohs hardness
3-4
Color
Light green
Luster
Vitreous
Streak
White
Density
3.36
Cleavage
without visible cleavage
Transparency
Transparent
Crystal system
Orthorhombic

Diagnostic features

## Identification Pauflerite is primarily identified by its characteristic, vivid blue color, its occurrence as small, platy crystals forming rosette-like aggregates, and its specific geological environment – oxidized uranium-vanadium deposits in sandstones. ## Distinguishing from Similar Minerals It can be confused with other secondary vanadium sulfates, such as minasragrite or schklaryite, which also have a blue color. Definitive differentiation requires advanced analytical methods, such as X-ray diffraction (XRD) or chemical analysis (EDS), due to the microscopic size of the crystals. ## Crystal Forms Pauflerite forms very thin, platy crystals with a hexagonal or rhombic outline. These crystals often combine into rosette-like or spherical aggregates, and also form thin coatings and crusts on the surface of the host rock.

Geological environment

## Genesis Pauflerite is a secondary mineral, formed in the oxidation zone of uranium-vanadium deposits found in sandstones. It forms as a result of the weathering of primary vanadium-bearing minerals, likely under low pH (acidic) conditions. ## Mineral Associations It co-occurs with other secondary vanadium and uranium minerals. At the type locality (Blue Cap Mine), it was found in association with minerals such as schklaryite, minasragrite, metarossite, pascoite, sherwoodite, as well as gypsum and quartz. ## Localities The only confirmed occurrence of pauflerite in the world is its type locality – the Blue Cap Mine in San Juan County, Utah, USA. This area is rich in uranium-vanadium deposits of the Salt Wash Member (Morrison Formation).

Rarity

Extremely rare

For collectors

## Quality Criteria The quality of a pauflerite specimen is primarily assessed based on the richness and coverage of the host rock surface by microcrystals. The most valued samples are those with clearly formed, rosette-like aggregates of intense blue color. Contrast with the light host rock (sandstone) also enhances the visual appeal of the specimen. Due to the microscopic nature of the mineral, specimens are evaluated under magnification. ## Popular Localities All known pauflerite specimens come from a single location in the world – the Blue Cap Mine in La Sal, Utah, USA. This locality is therefore the sole source of this mineral for collectors.

Care and storage

## Cleaning Pauflerite specimens are extremely delicate and usually occur as coatings on the host rock. Mechanical or chemical cleaning is not recommended. Any attempts at cleaning may irreversibly destroy the microscopic crystals. It is best to leave the specimen undisturbed. ## What to Avoid Avoid contact with water and chemicals, which can dissolve or damage the mineral. Protect it from vibrations, impacts, and abrasion. Due to its probable instability, avoid extreme temperatures and humidity. ## Storage It is recommended to store specimens in sealed, lidded "micromount" boxes, which protect against dust, moisture, and mechanical damage. Display should be away from direct sunlight and heat sources.

External references

Sources

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