Sigogglinite

Chemical formula: [Pb₂+₆Zn₂+(OH)₈](S₆+O₄)₃·₃H₂O

Sigogglinite is a rare, secondary lead and zinc mineral, forming small, tabular crystals of white color and pearly luster.

## Characteristics Sigogglinite is a hydrated hydroxyl sulfate of lead and zinc. It occurs as very small, hexagonal or pseudohexagonal tabular crystals, not exceeding 0.2 mm. These crystals form rosette-like or spherical aggregates, as well as thin coatings and efflorescences. Due to the small size of the crystals, its macroscopic features are difficult to observe without magnification. ## Physical Properties The mineral is characterized by a Mohs hardness of approximately 2-3. It has a pearly luster, especially visible on cleavage planes. It is transparent to translucent. The calculated density is 5.23 g/cm³. ## Colors and Varieties Sigogglinite is colorless to white. No varieties have been distinguished. ## History and Name The mineral's name comes from its discovery locality – the Sigoggl mine, located in the Goms Valley, Valais Canton, Switzerland. It was approved as a new mineral species by the International Mineralogical Association (IMA) in 2011 (IMA2011-011). It was described by Nicolas Meisser and his colleagues in 2013. ## Uses Sigogglinite has no industrial significance. It is solely an object of interest for collectors specializing in rare minerals or secondary oxidation zone minerals.

Properties

Mohs hardness: 2-3
Luster: Pearly
Streak: White
Density: 5.23
Cleavage: Perfect on {0001}
Fracture: Uneven
Transparency: Transparent to translucent
Crystal system: Trigonal

Diagnostic features

## Identification Identification of sigogglinite is possible almost exclusively using advanced analytical methods, such as Raman spectroscopy or X-ray diffraction (XRD), combined with chemical analysis (EDS). Visually, it is practically impossible to distinguish from many other white, secondary sulfate minerals without a detailed analysis of the paragenetic context and locality. ## Distinction from Similar Minerals It can be confused with other microcrystalline, white sulfates, such as anglesite, cerussite, gypsum, or other rare lead sulfates. Distinction requires specialized laboratory tests. Co-occurrence with other rare lead and zinc minerals in a specific environment is a key indicator. ## Crystal Forms It forms thin, hexagonal or pseudohexagonal tablets that combine into rosettes, spherulitic aggregates, and coatings on the surface of the host rock.

Geological environment

## Genesis Sigogglinite is a secondary mineral, forming in the oxidation zones of polymetallic ore deposits rich in lead and zinc. It forms as a result of the weathering of primary sulfides, such as galena and sphalerite, in the presence of sulfate-rich waters. It forms under low-temperature conditions, often in vugs and fractures in rocks. ## Mineral Associations At the type locality (Sigoggl mine, Switzerland), it co-occurs with anglesite, cerussite, gypsum, hemimorphite, quartz, sphalerite, galena, chalcopyrite, and pyrite. ## Localities The only confirmed and described occurrence of sigogglinite in the world is its type locality: the Sigoggl mine, in the Goms Valley, Valais Canton, Switzerland.

Rarity

Extremely rare

For collectors

## Quality Criteria As a "micromount" type mineral, the value of a specimen is primarily determined by the richness and aesthetics of the crystal aggregates visible under a microscope. Specimens with well-formed, sharp rosettes or dense crystalline coatings on a contrasting substrate are most highly prized. Confirmation of identification using analytical methods is also important, as it significantly increases the value and credibility of the specimen.

Care and storage

## Cleaning Sigogglinite specimens are extremely delicate and small. Mechanical cleaning should be avoided. If absolutely necessary, compressed air can be used from a safe distance to remove dust. Any contact with water or other liquids is inadvisable. ## What to Avoid Contact with acids and other chemicals that could dissolve it must be strictly avoided. The mineral is sensitive to shock and abrasion. It should not be heated or exposed to ultrasound. ## Storage Specimens should be stored in stable, sealed "micromount" containers to protect them from dust, mechanical damage, and sudden changes in humidity. Store away from sources of vibration.

Sources

IMA Mineral List (CNMNC)