Aiolosite
Chemical formula: Na<sub>2</sub>(Na<sub>2</sub>Bi<sup>3+</sup>)(S<sup>6+</sup>O<sub>4</sub>)<sub>3</sub>Cl
Aiolosite is an extremely rare sodium bismuth sulfate, forming colorless, microscopic crystals in volcanic fumaroles.
Properties
- Luster
- Vitreous
- Streak
- White
- Density
- 4.10
- Transparency
- Transparent
- Crystal system
- Trigonal
Diagnostic features
## Identification Identification of aiolosite based on visual characteristics is impossible. The only method for certain identification is advanced laboratory techniques, such as X-ray diffraction (XRD) and chemical analysis using an electron microprobe (EDS/WDS). A preliminary indication can only be its occurrence in the specific fumarole environment on Vulcano island. ## Differentiation from Similar Minerals It can be confused with numerous other colorless, microscopic minerals formed in fumaroles, such as sassolite or other sulfates. Differentiation requires specialized analysis of chemical composition (characteristic presence of sodium and bismuth) and crystal structure. ## Crystal Forms Aiolosite forms thin, hexagonal crystals with a tabular habit, flattened along the {0001} plane. They often occur as aggregates. Combinations of different rhombohedral forms can give crystal aggregates an appearance similar to an octahedron.
Geological environment
## Genesis Aiolosite is a mineral of volcanic origin, formed by sublimation. It crystallizes directly from hot gases (fumaroles) at a temperature of approximately 300-400°C. It is a typical product of high-temperature exhalative activity. ## Mineral Associations This mineral occurs in close association with other rare fumarolic sublimates. The most common associated minerals include bismuthinite, sassolite, and minerals from the demicheleite series (demicheleite-(Br), demicheleite-(Cl), demicheleite-(I)). ## Localities The only confirmed locality of aiolosite in the world is its type locality – the La Fossa crater on the volcanic island of Vulcano, part of the Aeolian Islands archipelago in Italy.
Rarity
Extremely rare
For collectors
## Quality Criteria In the case of a micromineral like aiolosite, the collector's value of a specimen depends on the abundance of crystals on the rock matrix, their sharpness, and development. Specimens with well-identified associated minerals, which confirm the paragenesis, are also highly valued. The value is almost exclusively scientific and systematic. ## Popular Localities The only specimens that can be found in collections come from the type locality – the La Fossa crater on Vulcano island in Italy. Obtaining material from this location is limited and requires specialized expeditions.
Care and storage
## Cleaning Cleaning aiolosite specimens is absolutely inadvisable. The crystals are extremely small and fragile, and any attempt at mechanical or chemical cleaning, even with water, risks their irreversible destruction. Specimens should be treated as inviolable. ## What to Avoid Avoid all vibrations, shocks, and contact with any liquids. As a product of fumarolic sublimation, it may be soluble in water or unstable under conditions of elevated humidity. It should be protected from temperature changes and direct light. ## Storage Aiolosite specimens must be stored in specialized, tightly sealed "micromount" boxes. This provides protection against dust, moisture, and mechanical damage. The box should be stored in a stable, dry place.