Chlormanganokalite
Chemical formula: K₄Mn²⁺Cl₆
Chlormanganokalite is a rare potassium and manganese halide, occurring as small, yellow crystals in volcanic environments.
Properties
- Mohs hardness
- 2.5
- Color
- Champagne, lemon- to canary-yellow.
- Luster
- Vitreous
- Streak
- White
- Density
- 2.31
- Cleavage
- Perfect on {0001}
- Fracture
- Conchoidal
- Transparency
- Transparent
- Crystal system
- Trigonal
Diagnostic features
## Identification Key diagnostic features include its intense yellow color, occurrence as small, tabular crystals in products of volcanic activity (fumaroles), and its instability upon contact with moisture. The reaction to moisture (dissolution) is one of its most characteristic features. ## Distinguishing from Similar Minerals It can be confused with native sulfur, which also forms yellow crystals in volcanic environments. However, chlormanganokalite differs in crystal habit (trigonal, not orthorhombic like sulfur) and, most importantly, in its water solubility, whereas sulfur is insoluble. ## Crystal Forms Crystals are typically small, tabular in habit, often with visible trigonal or hexagonal outlines. It occurs as single crystals, small groups, and also as crusts and coatings on volcanic rocks.
Geological environment
## Genesis Chlormanganokalite is a mineral of volcanic origin. It forms by sublimation from hot gases (exhalations) in volcanic fumaroles, crystallizing directly from the gas phase onto cooler rock surfaces. It is a typical mineral of high-temperature, dry volcanic environments. ## Mineral Associations It most often co-occurs with other halides and sulfates formed under similar conditions, such as halite, sylvite, kremersite, and also hematite. ## Localities The most important and classic locality for chlormanganokalite is the Vesuvius-Somma volcanic complex in Italy, where it was discovered. It is also known from the fumaroles of Tolbachik volcano on the Kamchatka Peninsula in Russia.
Rarity
Very rare
For collectors
## Quality Criteria Specimens with well-formed, sharp crystals of intense, pure yellow color are most valued by collectors. Crystal size is also important – the larger the crystals, the more valuable the specimen, although they rarely exceed a few millimeters. A contrasting, dark rock matrix on which the crystals are embedded enhances attractiveness. ## Popular Localities By far the most sought-after specimens come from the classic locality – Vesuvius in Italy. Specimens from Tolbachik volcano in Russia are also valued in specialized collections.
Care and storage
## Cleaning The mineral is water-soluble and very hygroscopic. It must absolutely not be cleaned wet. To remove dust, a very soft, dry brush can be used, or contaminants can be carefully blown off with compressed air from a distance. ## What to Avoid Any contact with water, water vapor, and humid air, which lead to rapid decomposition of the mineral, should be avoided. It should be protected from chemicals, acids, and detergents. It is very soft and brittle, so shocks and friction should be avoided. ## Storage Specimens of chlormanganokalite must be stored in conditions of controlled, low humidity. It is best to keep them in airtight, sealed containers (so-called "perky boxes") along with a desiccant (e.g., silica gel). Exposure to temperature changes and direct sunlight should be avoided.