Godovikovite
Chemical formula: (N<sup>3-</sup>H<sub>4</sub>)Al(S<sup>6+</sup>O<sub>4</sub>)<sub>2</sub>
Godovikovite is a rare ammonium aluminum sulfate, occurring as a product of volcanic activity or burning mine dumps.
Properties
- Mohs hardness
- 2
- Luster
- Vitreous
- Streak
- White
- Density
- 2.59
- Cleavage
- Perfect on {0001}
- Fracture
- Uneven
- Transparency
- Transparent to translucent
- Crystal system
- Trigonal
Diagnostic features
## Identification Godovikovite can be identified by its occurrence in specific environments – on burning coal dumps or near volcanic fumaroles. Its characteristic white, earthy, or powdery coatings are distinctive. A key diagnostic feature is its water solubility. ## Distinguishing from Similar Minerals It can be confused with other white secondary sulfates such as millosevichite, alunogen, or tschermigite. It differs from tschermigite (ammonium aluminum sulfate) by its different crystallographic system and optical properties. Differentiation from other similar minerals often requires advanced analytical methods, such as X-ray diffraction (XRD). ## Crystal Forms Crystals are rare and very small, usually in the form of thin, hexagonal plates, often grouped into rosette aggregates. Most commonly, it occurs as earthy masses, powdery coatings, and brittle crusts.
Geological environment
## Genesis Godovikovite is a secondary mineral, forming under specific, hot, and acidic conditions. It forms as a sublimation product at temperatures from 100 to 250°C. Its formation is associated with volcanic fumarole activity or, more commonly, with processes occurring on burning mine dumps, where ammonia-rich gases and sulfur oxides react with each other. ## Mineral Associations It co-occurs with other minerals formed under similar conditions, such as native sulfur, tschermigite, millosevichite, sal ammoniac, mascagnite, and boussingaultite. ## Localities The most important localities for this rare mineral are the burning dumps in Kopeysk in the Urals (Russia) – which is its type locality. It has also been reported in the Hungarian coal basin of Pécs-Vasas, in the Marcel mine in Radlin (Poland), and as a product of volcanic activity on the Kamchatka Peninsula (Tolbachik and Mutnovsky volcanoes) in Russia.
Rarity
Rare
For collectors
## Quality Criteria For collectors, specimens with well-formed, even microscopic, crystals in the form of hexagonal plates or rosettes are of the highest value. Rich crusts on the original matrix rock are also prized. Due to the nature of the mineral, purity and size are not key criteria – the quality and richness of crystallization are paramount. ## Popular Localities The most classic and valued specimens come from the discovery site – the burning dumps in Kopeysk, Southern Urals, Russia. Specimens from Polish dumps, e.g., from Radlin, are also sought after by collectors specializing in Polish minerals.
Care and storage
## Cleaning Godovikovite specimens are very delicate and water-soluble. Mechanical cleaning is highly risky. If necessary, compressed air can be used to remove dust, but this should be done from a distance and with minimal force. ## What to Avoid Contact with water and other liquids, which will immediately dissolve the mineral, must be strictly avoided. Godovikovite is sensitive to moisture, so it should be protected from humid air. It is also very soft and brittle, susceptible to mechanical damage. ## Storage Storage requires airtight conditions. It is best to place the specimen in a sealed container (e.g., a "perky box") with a desiccant (silica gel). It should be kept away from heat sources and protected from shocks.