Bubnovaite

Chemical formula: K₂Na₈Ca(S⁶⁺O₄)₆

Bubnowaite is a rare, water-soluble sulfate of potassium, sodium, and calcium, forming colorless or light blue crystals in volcanic fumaroles.

## Characteristics Bubnowaite is a complex sulfate of potassium, sodium, and calcium, occurring as small, tabular or bladed crystals, which often form fan-like or rosette-shaped aggregates. The crystals are typically colorless or have a delicate, light blue hue. This mineral is a product of volcanic activity, crystallizing directly from volcanic gases in fumaroles. ## Physical Properties Bubnowaite is characterized by low hardness, ranging from 2 to 3 on the Mohs scale, making it a very soft and brittle mineral. Its density, calculated from crystallographic data, is 2.656 g/cm³. It is transparent and has a white streak. Due to its water solubility, it is an unstable mineral in humid environments. ## Colors and Varieties This mineral occurs in a limited color range, mainly as colorless or light blue. No color varieties or commercial varieties have been distinguished. ## History and Name Bubnowaite was officially recognized as a new mineral by the International Mineralogical Association (IMA) in 2017. Its name honors Natalia Alexandrovna Bubnova (born 1944), a Russian crystallographer and specialist in crystal chemistry, for her contributions to mineralogy. It was discovered in volcanic exhalation products in Kamchatka. ## Uses Due to its rarity, small crystal size, and chemical instability (water solubility), bubnowaite has no industrial applications. It is of purely scientific and collector's interest.

Properties

Mohs hardness
2-3
Streak
White
Density
2.656
Transparency
Transparent
Crystal system
Trigonal

Diagnostic features

## Identification Bubnowaite can be identified by its occurrence in a specific environment – as a sublimate in active volcanic fumaroles. Its small, tabular crystals, which are light blue or colorless, and its low hardness are characteristic. A key diagnostic feature is its water solubility. ## Distinguishing from Similar Minerals This mineral can be confused with other sulfates found in similar environments, such as aphthitalite or langbeinite. Distinguishing it from these minerals without specialized tests (e.g., X-ray diffraction) is very difficult. The reaction to water is an important clue but does not allow for unambiguous identification. ## Crystal Forms Bubnowaite crystals are usually very small, with a tabular or bladed habit. They often form radial or fan-shaped aggregates and crusts on volcanic rocks.

Geological environment

## Genesis Bubnowaite is a fumarolic mineral. It forms by sublimation from hot volcanic gases rich in sulfur, at temperatures above 400°C. It crystallizes directly on the surface of volcanic rocks near exhalation vents. ## Mineral Associations This mineral co-occurs with other sulfates formed under similar conditions, such as aphthitalite, langbeinite, arcanite, as well as tenorite and hematite. ## Localities The only confirmed locality for bubnowaite in the world is its type locality – the Naboko cinder cone, formed during the Great Fissure Eruption of Tolbachik volcano in Kamchatka, Russia.

Rarity

Very rare

For collectors

## Quality Criteria The most valuable bubnowaite specimens are those with well-formed, visible crystals of intense, light blue coloration. Rich crusts covering a fragment of the rock matrix are also prized. Due to the small size of the crystals, specimens are usually evaluated under magnification. Purity and lack of mechanical damage are crucial, as is the stability of the specimen. ## Popular Localities All known collector specimens come from a single location in the world – Tolbachik volcano in Kamchatka, Russia. Material from this locality is extremely rarely available on the market.

Care and storage

## Cleaning Bubnowaite specimens must not be cleaned with water or any liquids, as the mineral is soluble in them. Only very careful dust removal with a soft brush or a low-pressure stream of compressed air is permissible. ## What to Avoid Absolute avoidance of contact with water, water vapor, and high humidity is essential, as these can quickly damage or completely destroy the specimen. The mineral must be protected from all chemicals, acids, and detergents. It is also very soft and brittle, so shocks and contact with harder minerals should be avoided. ## Storage Bubnowaite requires storage in conditions of controlled, low humidity. The best solution is a sealed container (e.g., a "perky box") with a desiccant (e.g., silica gel). It should be stored at a stable temperature, away from direct sunlight.

External references

Sources

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