Relianceite-(K)

Chemical formula: K₄Mg(V⁴⁺O)₂((C₂)⁶⁺O₄)(PO₃OH)₄(H₂O)₁₀

Relianceite-(K) is an extremely rare phosphate mineral, found as microscopic, blue crystals in oxidized uranium-vanadium rocks.

## Characteristics Relianceite-(K) is a hydrated potassium, magnesium, and vanadium phosphate, belonging to the group of secondary minerals. It occurs as very small, bladed or tabular crystals, rarely exceeding 0.2 mm in length. It forms rosetted or radial aggregates of an intense blue color. It is a transparent mineral with a vitreous luster. ## Physical Properties Due to the microscopic size of the crystals, many physical properties have not been fully determined. Hardness is too low to be measured by standard methods, but it is estimated to be around 2 on the Mohs scale. The density calculated from the formula and unit cell parameters is 2.41 g/cm³. ## Colors and Varieties This mineral is characterized by a uniform, intense blue color. No other color varieties or trade names have been observed. ## History and Name Relianceite-(K) was first described in 2023 by Anthony R. Kampf and his team. The name comes from the Reliance mine in Mesa County, Colorado (USA), where the mineral was discovered. The "-(K)" suffix in the name indicates the dominance of potassium (K) in a specific position in the crystal structure, distinguishing it from hypothetical, yet undiscovered analogs with other elements.

Properties

Mohs hardness
2.5
Color
Sky blue
Luster
Vitreous
Streak
Very pale blue
Density
2.111
Cleavage
Perfect on {010}
Fracture
Splintery
Transparency
Transparent
Crystal system
Monoclinic

Diagnostic features

## Identification Characteristic features of Relianceite-(K) include its intense blue color, vitreous luster, and occurrence as small, bladed crystals forming radial aggregates. Key to identification is its specific geological environment – oxidation zones of uranium-vanadium deposits in sandstones. ## Distinguishing from Similar Minerals It can be confused with other blue secondary vanadium minerals, such as sherwoodite or ankinovichite. Definitive distinction requires advanced analytical methods, such as Raman spectroscopy or X-ray diffraction (XRD), due to its microscopic size and visual similarity to other minerals in this group. ## Crystal Forms Crystals are very small, elongated, and flattened, with a bladed or tabular habit. They usually occur as radial or rosetted clusters and aggregates, growing on the host rock.

Geological environment

## Genesis Relianceite-(K) is a secondary mineral that crystallizes under low-temperature conditions in the oxidation zones of uranium-vanadium deposits. It forms as a result of groundwater interaction with primary uranium and vanadium minerals (such as uraninite and montroseite) in the presence of phosphorus, magnesium, and potassium, derived from sedimentary rocks (sandstones) and clay minerals. ## Mineral Associations This mineral co-occurs with other rare secondary minerals, such as ansermetite, duttonite, hughesite, lasalite, as well as with gypsum, quartz, and clay minerals. ## Localities The only confirmed occurrence (type locality) of Relianceite-(K) in the world is the Reliance mine, located in the Uravan District, Mesa County, Colorado, USA.

Rarity

Extremely rare

For collectors

## Quality Criteria The quality of Relianceite-(K) specimens is primarily assessed based on the richness and aesthetics of crystal aggregates on the rock matrix. Most valued are specimens with clearly formed, radial clusters of intense blue color that contrast well with the lighter sandstone background. Due to the microscopic nature of the mineral, the size of individual crystals is not a key criterion; rather, the overall area covered by the mineral is important. ## Popular Localities The only source of specimens of this mineral is its type locality – the Reliance mine in Colorado, USA. All specimens available on the collector's market originate from this single location.

Care and storage

## Cleaning Specimens should be handled with utmost care. Mechanical cleaning is not recommended due to extreme fragility and small crystal size. If absolutely necessary, compressed air can be used from a safe distance to remove loose dust particles. ## What to Avoid Avoid contact with water, chemicals, and sudden temperature changes. The mineral is likely sensitive to moisture and may undergo dehydration or chemical alteration. It should not be heated or exposed to ultrasound. ## Storage Relianceite-(K) specimens should be stored exclusively in specialized, sealed "micromount" boxes, protecting them from dust, mechanical damage, and humidity changes. Avoid exposure to direct sunlight, which may cause color fading.

External references

Sources

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