Svornostite-(K)

Chemical formula: K₂Mg(U⁶⁺O₂)₂(S⁶⁺O₄)₄·8H₂O

Swornostite-(K) is a rare, hydrated uranyl, magnesium, and potassium sulfate, forming transparent, pale yellow tabular crystals.

## Characteristics Swornostite-(K) is a complex, hydrated uranyl, magnesium, and potassium sulfate. This mineral occurs as small, tabular or bladed crystals, rarely exceeding 1 mm in length. They typically form fragile, rosette-like or radial aggregates. It is a secondary mineral, meaning it forms as a result of weathering processes of other uranium minerals. ## Physical Properties Swornostite-(K) is a very soft mineral with a Mohs hardness of 2, meaning it can be scratched with a fingernail. It has a density of approximately 3.27 g/cm³. The crystals exhibit a vitreous luster and are transparent to translucent. Due to its uranium content, this mineral is strongly radioactive. ## Colors and Varieties This mineral is characterized by a pale yellow color and a pale yellow streak. No distinct color varieties or commercial varieties have been identified. ## History and Name Swornostite-(K) was first described in 2015 by a team of mineralogists led by Jakub Plášil. Its name comes from the historical name of the Svornost mine in Jáchymov (Czech Republic), where it was discovered. This mine is its type locality. The suffix "-(K)" in the name indicates the dominance of potassium in a specific position within the mineral's crystal structure.

Properties

Mohs hardness
2
Luster
Vitreous
Streak
Pale yellow
Density
3.268
Cleavage
on {100} and {010}.
Fracture
Irregular/Uneven
Transparency
Transparent,Translucent
Crystal system
Orthorhombic

Diagnostic features

## Identification Key diagnostic features of swornostite-(K) include its pale yellow color, tabular crystal habit forming rosette-like aggregates, and occurrence in paragenesis with other secondary uranium minerals. Strong radioactivity is also an important indicator. However, definitive identification requires advanced analytical methods, such as X-ray diffraction (XRD). ## Distinguishing from Similar Minerals Swornostite-(K) can be confused with many other yellow secondary uranyl minerals, such as zippeite, johannite, or uranophane. Distinguishing it based on visual characteristics is practically impossible and requires specialized laboratory tests to determine its chemical composition and crystal structure. ## Crystal Forms Crystals are most often thin-tabular or bladed, elongated along the crystallographic axis. They form characteristic, small aggregates with a rosette-like or radial habit, growing on host rocks.

Geological environment

## Genesis Swornostite-(K) is a secondary mineral, forming in the oxidation zones of uranium deposits. It forms as a result of weathering and alteration of primary uranium minerals, mainly uraninite, in an environment rich in sulfates, magnesium, and potassium. Its presence is associated with the activity of mine waters in old mining workings. ## Mineral Associations This mineral co-occurs with other secondary uranyl sulfates. At the type locality, it was found in association with gypsum, adolfpateraite, zippeite, uranopilite, and unspecified minerals from the zippeite group. ## Localities The only confirmed and described occurrence of swornostite-(K) is its type locality – the Geschieber vein in the Svornost mine in Jáchymov, Czech Republic. It is a mineral with an extremely limited range of occurrence.

Rarity

Extremely rare

For collectors

## Quality Criteria As a "micromount" type mineral, the collector's value of swornostite-(K) depends primarily on the quality and development of the crystals, rather than their size. Specimens with well-formed, sharp, undamaged crystals forming aesthetic, rosette-like aggregates are most highly prized. Contrast with the rock matrix and the richness of associations with other rare uranium minerals are also important. ## Popular Localities The only source of collector specimens is the Svornost mine in Jáchymov, Czech Republic. Due to its extreme rarity, specimens of this mineral practically do not appear on the open market and are mainly found in institutional collections and among specialized collectors of uranium minerals.

Care and storage

## Cleaning Swornostite-(K) specimens are extremely delicate and fragile, and therefore should not be cleaned mechanically or chemically. Any attempts at cleaning may lead to irreversible damage to the crystals. It is safest to leave the specimen undisturbed. ## What to Avoid Contact with water and chemicals should be strictly avoided. The mineral is very soft and sensitive to shocks and temperature changes. As a uranium mineral, it is strongly radioactive and requires specialized, safe handling. Direct contact and inhalation of dust should be avoided. ## Storage Specimens should be stored in sealed, padded containers, preferably "micromount" type, to protect them from mechanical damage and vibrations. Store away from other minerals that could be damaged by radiation. It is necessary to properly label the container with radioactivity information.

External references

Sources

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