Wittite B

Chemical formula: Pb₈Bi₁₀S₂₃

Wittichenite B is a rare lead-bismuth sulfosalt mineral, forming acicular or fibrous aggregates with a metallic luster.

## Characteristics Wittichenite B is a complex lead-bismuth sulfosalt, belonging to the wittichenite series. It occurs as fine, acicular or fibrous crystals, which often form felted, radial, or chaotic aggregates. Its color is steel-gray to tin-white, and it may tarnish or become covered with a darker coating over time. Due to the small size of the crystals, its macroscopic features are difficult to observe without magnification. ## Physical Properties This mineral is characterized by a metallic luster and is opaque. Its Mohs hardness is low, approximately 2, meaning it is soft and can be scratched with a fingernail. It is a heavy mineral due to its high lead and bismuth content. ## History and Name The name "wittichenite" comes from the Wittichen mine in Germany, where minerals of this group were first identified. It was originally described by Johan Georg Lorenz Gustaf (G.) Flink in 1925. Wittichenite B was later defined as a distinct mineral species within the wittichenite series, subtly differing in chemical composition and structure from other minerals in this group.

Properties

Mohs hardness: 2
Luster: Metallic
Streak: Black
Density: 7.11
Cleavage: Perfect on {010}
Fracture: Uneven
Transparency: Opaque
Crystal system: Monoclinic

Diagnostic features

## Identification Wittichenite B is difficult to identify without advanced analytical methods, such as chemical analysis (EDS) and X-ray diffraction (XRD). Visually, it is characterized by a steel-gray color, metallic luster, and the form of fine, acicular or fibrous crystals forming aggregates. Its low hardness (approx. 2) is an auxiliary feature. ## Distinguishing from Similar Minerals It can be confused with many other lead-bismuth sulfosalts, such as aikinite, bismuthinite, jamesonite, or other minerals from the wittichenite group. All these minerals have a similar appearance (gray, metallic, acicular). Definitive differentiation is possible almost exclusively based on chemical composition and crystal structure analysis. ## Crystal Forms It forms elongated, acicular or bladed crystals, often with a rectangular cross-section. They usually occur as tangled, fibrous or radial aggregates intergrown with the host rock or filling small fissures.

Geological environment

## Genesis Wittichenite B is a hydrothermal mineral. It forms in ore veins, usually in paragenesis with other bismuth, lead, and copper sulfides and sulfosalts. Its crystallization occurs under medium and low-temperature conditions. ## Mineral Associations It most commonly co-occurs with minerals such as quartz, calcite, pyrite, chalcopyrite, bismuthinite, aikinite, as well as other rare sulfosalts. ## Localities The most important and classic localities for this mineral are the Fäboliden mine in Lycksele (Lappland, Sweden) and the historical locality in the Wittichen mine in the Black Forest (Baden-Württemberg, Germany). It is also known from several other localities worldwide where bismuth-rich deposits occur.

Rarity

Very rare

For collectors

## Quality Criteria The quality of a wittichenite B specimen primarily depends on the richness and visibility of its aggregates on the rock matrix. The most prized specimens are those with clearly formed, dense clusters of acicular crystals, contrasting with the surrounding rock (e.g., with white quartz). Association with other rare minerals is also important. ## Popular Localities The most well-known and valued specimens by collectors come from the Swedish Fäboliden mine. Specimens from this locality are considered the best in the world for this species.

Care and storage

## Cleaning Wittichenite B specimens are extremely delicate and sensitive. Mechanical cleaning is highly inadvisable. If necessary, compressed air (from a safe distance) can be used to remove dust. Avoid contact with water and all chemicals. ## What to Avoid Absolutely avoid contact with water, acids, cleaning agents, and other chemicals that can cause its decomposition. The mineral is sensitive to oxidation, so its exposure to humid air should be limited. It is very soft and brittle, susceptible to mechanical damage. ## Storage It is recommended to store wittichenite B specimens in sealed, dry containers (e.g., "membrane boxes") or in stable conditions away from moisture and air pollutants. It should be protected from dust and physical damage.

Sources

IMA Mineral List (CNMNC)