Pizgrischite

Chemical formula: (Cu₁+,Fe₂+)Cu₁+₁₄Pb₂+Bi₃+₁₇S₂-₃₄

Pizgrischite is an extremely rare lead, bismuth, and copper sulfide, forming lead-gray, metallic aggregates within Alpine quartz veins.

## Characteristics Pizgrischite is a complex sulfosalt of the pavonite group, occurring as small, lath-like or acicular crystals, usually not exceeding 1 mm in length. These crystals form irregular, tangled aggregates. The mineral has a metallic luster and a lead-gray color, which is lighter on a fresh surface. ## Physical Properties Its hardness has not been precisely measured, but based on microhardness tests (VHN 181-209), it is estimated to be approximately 4 on the Mohs scale. It is a brittle and opaque mineral. The density, calculated based on chemical composition and unit cell parameters, is 6.31 g/cm³. ## Colors and Varieties Pizgrischite has a uniform, lead-gray color. No color or commercial varieties are known. ## History and Name The mineral's name comes from its discovery locality – Piz Grisch peak in Val d'Err (Graubünden canton, Switzerland). It was officially recognized as a new mineral species by the International Mineralogical Association (IMA) in 2005. It was described by mineralogists Nicolas Meisser, Joël Brugger, and others. ## Uses Due to its extreme rarity, pizgrischite has no practical applications. It is solely an object of scientific research and a valuable acquisition for specialized collectors of systematic minerals.

Properties

Mohs hardness: ~4
Luster: Metallic
Streak: Black
Density: 6.31
Cleavage: None
Transparency: Opaque
Crystal system: Monoclinic

Diagnostic features

## Identification Visual identification of pizgrischite is practically impossible without specialized equipment. It is recognized by its lead-gray color, metallic luster, and characteristic lath-like crystal form. Its occurrence in a specific mineral paragenesis at the only known locality is crucial. Definitive identification requires advanced analytical methods, such as X-ray microanalysis (EDS/WDS) and X-ray diffraction (XRD). ## Distinguishing from Similar Minerals Pizgrischite can be easily confused with other fine-grained, gray bismuth sulfosalts, such as bismuthinite, cosalite, or galenobismutite, with which it often co-occurs. Distinguishing them from each other is only possible through chemical analysis. ## Crystal Forms It forms elongated, lath-like or acicular crystals, often flattened. They usually occur as disordered, tangled aggregates embedded in quartz or other associated minerals.

Geological environment

## Genesis Pizgrischite forms under hydrothermal conditions, within Alpine-type quartz veins cutting two-mica gneisses. It is a product of crystallization from solutions rich in sulfur, copper, lead, and bismuth. ## Mineral Associations This mineral co-occurs with native bismuth, bismuthinite, galenobismutite, cosalite, and minerals from the lillianite-gustavite series. The entire paragenesis is usually embedded in quartz. ## Localities The only confirmed locality of pizgrischite in the world is its type locality: quartz veins in the Piz Grisch area in Val d'Err, Graubünden canton, Switzerland.

Rarity

Extremely rare

For collectors

## Quality Criteria As a microscopic mineral, the collector's value of pizgrischite primarily depends on the richness of the aggregates on the rock matrix. Specimens with clearly visible, well-formed aggregates of lath-like crystals are most valued. The presence of other rare associated minerals, such as native bismuth or galenobismutite, is an additional asset. ## Popular Localities All known collector specimens come from a single location in the world – the type locality in Piz Grisch, Switzerland. Material from this locality is extremely limited.

Care and storage

## Cleaning Pizgrischite specimens should only be dry-cleaned, using a soft brush or compressed air to remove dust. Due to its rarity and potential chemical sensitivity, the use of water and any cleaning agents is discouraged. ## What to Avoid Avoid contact with acids, detergents, and other chemicals that can permanently damage the mineral's surface. As a sulfide, it may be sensitive to moisture and oxidation, so it should be protected from prolonged exposure to humid air. ## Storage It is recommended to store specimens in a dry and stable environment, preferably in a closed "perky box". This protects the mineral from dust, moisture, and accidental mechanical damage.

Sources

IMA Mineral List (CNMNC)