Paganoite

Chemical formula: Ni₂+Bi₃+O(As₅+O₄)

Paganoite is a very rare nickel and bismuth arsenate, forming characteristic, bright green coatings and aggregates.

## Characteristics Paganoite is a nickel and bismuth arsenate, occurring as microscopic, tabular crystals up to 0.2 mm in size. It forms rosetted aggregates, spherical clusters, and thin coatings and crusts on the host rock. Its most characteristic feature is its intense, bright green or yellowish-green color. ## Physical Properties Paganoite crystals exhibit a vitreous luster. The mineral is transparent to translucent. Due to the microscopic size of the crystals, the hardness has not been precisely determined, but it is estimated to be around 3 on the Mohs scale. The density calculated based on the formula and unit cell parameters is 6.65 g/cm³. ## Colors and Varieties Paganoite occurs in uniform, bright shades of green, from emerald green to yellowish-green. No varieties have been distinguished. ## History and Name The mineral was discovered in the dumps of the former uranium mine Johanngeorgenstadt in the Ore Mountains (Saxony, Germany). It was described in 2002 by Werner Krause, Heinz-Jürgen Bernhardt, H. Effenberger, and U. Kolitsch. The name honors Renato Pagano (born 1936), an Italian mineral collector and author, known for his knowledge of rare mineral species and their photography. ## Uses Paganoite has no industrial applications. It is solely an object of interest for collectors specializing in rare minerals and for scientists.

Properties

Mohs hardness: 3
Luster: Vitreous
Streak: Light green
Density: 6.65
Cleavage: Good on {010}
Fracture: Uneven
Transparency: Transparent to translucent
Crystal system: Monoclinic

Diagnostic features

## Identification Paganoite is primarily recognizable by its characteristic, bright green color, its occurrence as small, rosetted aggregates, and its association with other rare bismuth and nickel arsenates. Positive identification requires advanced analytical methods, such as Raman spectroscopy or chemical analysis (EDS). ## Distinguishing from Similar Minerals Paganoite can be confused with other green secondary nickel minerals, such as annabergite, which, however, forms acicular crystals. Visually similar might also be mixite, which crystallizes in the hexagonal system and often has a more bluish tint. Definitive differentiation from these and other rare arsenates (e.g., preisingerite, walentaite) is only possible through laboratory analysis. ## Crystal Forms Crystals are very small, tabular, with a pseudohexagonal habit. They typically form rosetted or spherical aggregates and thin crusts.

Geological environment

## Genesis Paganoite is a secondary mineral, formed in the oxidation (weathering) zones of polymetallic ores rich in bismuth, nickel, and arsenic. It forms in cavities and fissures in rocks, most often on a quartz substrate. ## Mineral Associations This mineral co-occurs with other rare secondary minerals. In the type locality (Johanngeorgenstadt), it was found in association with quartz, bismutite, preisingerite, walentaite, atelestite, eulytine, and rooseveltite. In Jáchymov, it co-occurs with arsenolite, annabergite, and erythrite. ## Localities Confirmed occurrences of paganoite are few. The most important ones include: - Johanngeorgenstadt in the Ore Mountains, Saxony, Germany (type locality). - Jáchymov (Svornost mine) in the Czech Republic. - Pucher Mine, Schneeberg, Saxony, Germany.

Rarity

Very rare

For collectors

## Quality Criteria The most highly prized paganoite specimens are those with rich, well-formed, spherical or rosetted aggregates of intense, bright green color, clearly contrasting with the host rock (preferably white quartz). The size of the aggregates and the coverage of the matrix surface are key factors influencing value. Due to the microscopic nature of the crystals, specimens are primarily evaluated under magnification. ## Popular Localities The best and most well-known specimens come from the type locality - Johanngeorgenstadt in Germany. Material from Jáchymov in the Czech Republic is also known, but usually forms less spectacular clusters.

Care and storage

## Cleaning Paganoite specimens should be cleaned only very carefully, using compressed air to remove dust. Due to its fragility and potential solubility, contact with water and other liquids should be avoided. Ultrasonic cleaning is absolutely forbidden. ## What to Avoid All chemicals, acids, and detergents should be avoided. The mineral is sensitive to abrasion and impact. It should not be heated or exposed to prolonged moisture. ## Storage Specimens should be stored under stable conditions, in closed, padded "micromount" boxes to protect them from mechanical damage, dust, and moisture. Exposure to direct sunlight should be avoided, although there is no evidence of fading.

Sources

IMA Mineral List (CNMNC)