Interliveingite

Chemical formula: Ag₁+Pb₂+₁₈As₃+₂₅S₂-₅₆

Interliveingite is a rare lead-silver sulfarsenide of lead, occurring as tiny, metallic-lustered crystals.

## Characteristics Interliveingite is a complex lead-silver sulfarsenide belonging to the sartorite group. This mineral forms very fine, acicular or hair-like crystals, which rarely exceed fractions of a millimeter in length. They usually occur as felted aggregates or coatings on other minerals, especially on the host dolomite. Due to the small size of the crystals, its macroscopic features are difficult to observe without magnification. ## Physical Properties Interliveingite crystals are characterized by a metallic luster. They are opaque and have a black color with a reddish internal reflection, visible in strong light. It is a relatively soft mineral. ## Colors and Varieties This mineral is homogeneous in composition and does not form color varieties. Its color is invariably black. ## History and Name Interliveingite was formally described as a new mineral in 2017 by a team of mineralogists led by Danuta Topa. Its name honors Walter Henry

Properties

Mohs hardness: 3-3.5
Luster: Metallic
Streak: Red-brown
Density: 5.61
Cleavage: Good on {100}
Fracture: Uneven
Transparency: Opaque
Crystal system: Monoclinic

Diagnostic features

## Identification Identification of interliveingite is only possible using advanced laboratory methods, such as chemical analysis (EDS/WDS) and X-ray diffraction (XRD). In field conditions or in a collection, due to its microscopic size and similarity to other sulfosalts, it is impossible to unequivocally identify visually. ## Distinguishing from Similar Minerals It can be confused with many other black, metallic sulfosalts found in Lengenbach, such as liveingite, sartorite, baumhauerite, or dufrenoysite. Differentiation requires specialized analysis of chemical composition and crystal structure. ## Crystal Forms Interliveingite forms very fine, acicular or hair-like crystals, often entangled in felted aggregates. The crystals are elongated along the [010] axis.

Geological environment

## Genesis Interliveingite forms as a result of hydrothermal processes in Alpine dolomite deposits. It is a product of crystallization from solutions rich in arsenic, sulfur, lead, and silver at relatively low temperatures. ## Mineral Associations This mineral occurs in close association with other rare sulfosalts, such as liveingite, sartorite, baumhauerite, dufrenoysite, as well as with realgar, orpiment, and pyrite. All these minerals coexist in white, sugary dolomite. ## Localities The only confirmed occurrence of interliveingite in the world is the Lengenbach quarry in the Binn Valley (Binntal) in the canton of Valais, Switzerland. This is its type locality and, so far, the only known one.

Rarity

Extremely rare

For collectors

## Quality Criteria Given the microscopic nature of the mineral, its collector's value is strictly scientific. The most valuable specimens are those where interliveingite has been unequivocally identified by analytical methods. The quality of the specimen is determined by the abundance of crystals on the matrix and their association with other rare sulfosalts from Lengenbach. ## Popular Localities The only source of specimens is the Lengenbach quarry in Switzerland, considered one of the most important localities for rare sulfosalts worldwide.

Care and storage

## Cleaning Due to its extreme rarity and delicacy, interliveingite specimens should only be cleaned by professionals. Any attempts at mechanical or chemical cleaning can irreversibly damage the specimen. For dusty samples, a gentle stream of compressed air can be used from a safe distance. ## What to Avoid Avoid contact with any chemicals, including water. Do not expose it to ultrasound or high temperatures. The mineral is soft and brittle, so it should be protected from impacts and scratches. ## Storage Microscopic specimens are best stored in specialized micromount boxes, protecting them from dust and mechanical damage. Avoid exposure to direct sunlight and moisture.

Sources

IMA Mineral List (CNMNC)