Mellizinkalite
Chemical formula: K₃Zn²⁺₂Cl₇
Mellizinkalite is a very rare potassium zinc halide, forming tiny, colorless crystals in volcanic fumaroles.
Properties
- Color
- Yellow-brown to reddish brown
- Luster
- Vitreous
- Streak
- White
- Density
- 2.46
- Cleavage
- Perfect on {0001}
- Fracture
- Irregular/Uneven
- Transparency
- Transparent
- Crystal system
- Triclinic
Diagnostic features
## Identification Identification of mellizinkalite is impossible without advanced laboratory techniques, such as X-ray diffraction (XRD) and chemical analysis using an electron microprobe (EDS/WDS). In collecting or field conditions, identification is unfeasible. A characteristic feature is its occurrence in the specific environment of volcanic fumaroles. ## Differentiation from Similar Minerals It can be confused with other fine-crystalline, colorless halides found in the same environment, such as salammoniac (NH₄Cl) or halite (NaCl). Differentiation requires specialized analysis of chemical composition and crystal structure. ## Crystal Forms It forms very small, thin, tabular crystals with a hexagonal outline, often elongated and lath-like. It occurs as single, dispersed crystals or small, loose aggregates.
Geological environment
## Genesis Mellizinkalite is a mineral of volcanic origin. It forms by direct sublimation from volcanic gases (exhalations) in the environment of active fumaroles. It crystallizes at high temperatures from gases rich in chlorine, potassium, and zinc. ## Mineral Associations It co-occurs with other fumarolic minerals, such as salammoniac, halite, sylvite, cotunnite, as well as various metal chlorides, e.g., zinc and copper. ## Localities The only confirmed locality of mellizinkalite in the world is the Vesuvius-Somma volcanic complex in Campania, Italy. It has been identified in exhalative products associated with historical eruptions.
Rarity
Extremely rare
For collectors
## Quality Criteria As a "micromount" type mineral, the collector's value of a specimen primarily depends on the confirmation of its identity by a reputable laboratory. Samples with well-formed, though still microscopic, crystals that are rich in mellizinkalite and embedded on a stable matrix are most highly valued. Precise documentation of the locality and analysis is crucial. ## Popular Localities The only source of specimens is the fumaroles on Mount Vesuvius in Italy. Material from this location is highly prized by collectors specializing in systematic minerals and "micromounts."
Care and storage
## Cleaning Due to its extreme rarity, small crystal size, and water solubility, mellizinkalite specimens should not be cleaned in any way. Any attempt at cleaning risks irreversible destruction of the mineral. ## What to Avoid Contact with water, water vapor, and all chemicals must be absolutely avoided, as the mineral is hygroscopic and easily soluble. It must be protected from atmospheric moisture, temperature changes, and any shocks or vibrations. ## Storage Mellizinkalite specimens must be stored in specialized, airtight containers (so-called micromount boxes) under controlled, very low humidity conditions. Storage in a dry place, away from light and heat sources, is absolutely crucial for preserving the sample.