Lussierite

Chemical formula: Na<sub>10</sub>[(U<sup>6+</sup>O<sub>2</sub>)(S<sup>6+</sup>O<sub>4</sub>)<sub>4</sub>](S<sup>6+</sup>O<sub>4</sub>)<sub>2</sub>(H<sub>2</sub>O)<sub>3</sub>

Lussierite is an extremely rare, highly fluorescent sodium uranyl sulfate, forming tiny, yellow crystals.

## Characteristics Lussierite is a mineral from the uranyl sulfate group, forming small, prismatic crystals up to 0.2 mm long. They usually occur as efflorescences and aggregates. The mineral has an intense yellow color and a vitreous luster. Its most characteristic feature is very strong, green fluorescence in both shortwave and longwave ultraviolet light. It is a highly radioactive mineral. ## Physical Properties Lussierite crystals are transparent and exhibit a vitreous luster. Due to the small size and fragility of the crystals, its hardness and density have not been precisely measured. It is a brittle mineral. ## Colors and Varieties Lussierite occurs exclusively in yellow. No color varieties or commercial varieties are known. ## History and Name The mineral was approved by the International Mineralogical Association (IMA) in 2018. Its name honors Canadian mineralogist Daniel Lussier (born 1980) for his contributions to the study of uranium minerals. The type locality (locus typicus) is the Blue Lizard mine in San Juan County, Utah, USA. ## Uses Lussierite, as an extremely rare mineral occurring in microscopic quantities, has no industrial application. It is solely an object of scientific and collecting interest for specialists collecting rare uranium minerals.

Properties

Luster
Vitreous
Streak
Light yellow
Transparency
Transparent
Crystal system
Orthorhombic

Diagnostic features

## Identification Key diagnostic features of lussierite are its intense yellow color, habit of small prismatic crystals, and very strong green fluorescence under UV light. Its origin from the only known locality (Blue Lizard mine) is also a decisive clue. ## Distinguishing from Similar Minerals Lussierite can be confused with other yellow secondary uranium minerals such as zippeite, uranopilite, or natrozippeite. Certain differentiation from these minerals is usually impossible without advanced analytical techniques, such as X-ray diffraction (XRD) or chemical microanalysis (EDS). The characteristic shade of fluorescence and paragenesis can be helpful in identification. ## Crystal Forms The mineral forms elongated, prismatic crystals, which often arrange into radial aggregates, rosettes, or form thin coatings and crusts on the host rock.

Geological environment

## Genesis Lussierite is a secondary mineral that forms under specific post-mining conditions in uranium mines. It forms as a product of evaporation of sulfate-rich mine waters that have reacted with primary uranium ore (uraninite). It is a typical ephemeral (unstable) mineral. ## Mineral Associations This mineral co-occurs with other rare, secondary uranyl sulfates, such as bobcookite, plášilite, wetherillite, and also with gypsum. ## Localities The only confirmed occurrence of lussierite in the world is the Blue Lizard mine in Red Canyon, San Juan County, Utah, USA.

Rarity

Extremely rare

For collectors

## Quality Criteria The quality of lussierite specimens, which are usually micromounts, is assessed based on several criteria. The most important are the richness and coverage of the host rock by crystals, their size (even if submillimeter), sharpness, and luster. Specimens with well-formed, radial aggregates and those occurring in association with other rare uranium minerals are also highly valued. ## Popular Localities All known lussierite specimens available on the collector's market come from its type locality - the Blue Lizard mine in Utah, USA.

Care and storage

## Cleaning Lussierite is a water-soluble and very delicate mineral. It must absolutely not be cleaned wet. Only careful dust removal with a soft brush or a stream of compressed air from a safe distance is permissible. ## What to Avoid Avoid contact with water and other liquids that can dissolve it. As a hydrated mineral, it is sensitive to changes in humidity, which can lead to its dehydration and destruction. High temperatures should also be avoided. Due to radioactivity, appropriate precautions should be taken when handling specimens. ## Storage Lussierite specimens should be stored in tightly sealed containers (e.g., perky boxes) to ensure a stable humidity level. They should be kept away from other minerals that could be damaged by radiation. Each specimen must be clearly labeled as radioactive material.

Sources

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