Manganotychite
Chemical formula: Na₆Mn²⁺₂(CO₃)₄(S⁶⁺O₄)
Manganotychite is a rare sodium and manganese carbonate-sulfate, forming small, colorless or pink crystals in the isometric system.
Properties
- Mohs hardness
- 4
- Color
- Pale pink
- Luster
- Vitreous
- Streak
- White
- Density
- 2.70
- Cleavage
- None
- Fracture
- Conchoidal
- Transparency
- Transparent
- Crystal system
- Isometric
Diagnostic features
## Identification Field identification of manganotychite is practically impossible due to its rarity and resemblance to other minerals. In a collection, it is recognized by its characteristic, isometric crystal form (octahedra), vitreous luster, and occurrence in a specific geological environment. Certain identification requires advanced analytical methods, such as X-ray diffraction (XRD) or chemical analysis (EDS). ## Distinguishing from Similar Minerals It can be confused with the closely related tychite, from which it differs by the presence of manganese instead of magnesium – differentiation is only possible by analytical methods. It may also resemble other small, colorless evaporite minerals, but its isometric crystal form is quite characteristic. ## Crystal Forms Manganotychite crystals have an isometric habit, most often taking the form of acute octahedra {111}, and less frequently rhombic dodecahedra {110}. They occur as single, attached crystals in rock cavities.
Geological environment
## Genesis Manganotychite is a hydrothermal mineral, crystallizing in late stages from solutions rich in sodium, carbonates, and sulfates. It forms under specific conditions within fractures and cavities in sedimentary rocks, such as black shales, often in association with other rare minerals. ## Mineral Associations This mineral co-occurs with other rare carbonate and sulfate minerals. It is most commonly found in association with shortite, northupite, pyrite, quartz, and especially the related tychite. ## Localities The most important and classic locality for manganotychite is the diamond mine in Murfreesboro (Pike County) and the Magnet Cove area (Hot Spring County) in Arkansas, USA. It is also known from several localities in Russia, including the Kola Peninsula (Khibiny and Lovozero massifs) and the Ilmeny complex in the Ural Mountains. It has also been reported from the Ilimaussaq complex in Greenland.
Rarity
Very rare
For collectors
## Quality Criteria For collectors, the size and quality of crystal formation are most important. The most valued are sharp, transparent, well-formed octahedra with a noticeable pink color. It is also important for crystals to be embedded in an aesthetic rock matrix, which highlights their form. Specimens from classic localities, such as Arkansas, are particularly sought after. ## Popular Localities The most well-known and prized specimens come from historical finds in Arkansas, USA. High-quality crystals are also provided by the Russian alkaline massifs on the Kola Peninsula.
Care and storage
## Cleaning It is recommended to clean only with a soft, dry brush to remove dust. Avoid water and any chemical agents, as the mineral is soluble in acids and can react with water. ## What to Avoid Absolutely avoid contact with water, acids, and other liquids. The mineral is sensitive to moisture, which can lead to its slow decomposition. It should not be heated or exposed to sudden temperature changes. ## Storage Manganotychite specimens should be stored in a dry place, preferably in tightly sealed display boxes or containers with a desiccant. Protect from dust and direct contact with other, harder minerals.