Manganiceladonite
Chemical formula: KMgMn<sup>3+</sup>Si<sub>4</sub>O<sub>10</sub>(OH)<sub>2</sub>
Manganiceladonite is a rare, green mineral from the mica group, being the manganese analogue of celadonite, found in volcanic rocks.
Properties
- Mohs hardness
- 2-2.5
- Luster
- Dull
- Streak
- Pale green
- Density
- 2.95
- Cleavage
- Perfect on {001}
- Fracture
- Uneven
- Transparency
- Translucent
- Crystal system
- Monoclinic
Diagnostic features
## Identification Macroscopic identification of manganiceladonite is practically impossible. Its identification relies on chemical analysis (e.g., EDS) to confirm the presence of potassium, magnesium, manganese, and silicon in the absence of aluminum, and on X-ray diffraction (XRD) to determine the crystal structure. Its green color and earthy appearance in association with other manganese minerals can be an indication. ## Distinguishing from similar minerals It can be confused with other green secondary minerals of similar appearance, such as celadonite, glauconite, or various clay minerals. Celadonite is practically indistinguishable without chemical analysis (it contains iron instead of manganese). Glauconite usually forms characteristic granules (ooids) and has a slightly different composition. ## Crystal forms It forms microscopic, scaly crystals that occur as compact, earthy, or cryptocrystalline masses and coatings.
Geological environment
## Genesis Manganiceladonite is a low-temperature hydrothermal mineral. It forms as a result of the alteration of volcanic rocks, especially basalts, under oxidizing conditions. It occurs as a mineral filling gas vesicles and fractures in these rocks. ## Mineral associations It co-occurs with minerals typical of its formation environment, such as quartz, calcite, braunite, hollandite, cryptomelane, and other manganese oxides. ## Localities The most important and best-documented locality, which is also the type locality, is the Cerchiara mine in Liguria, Italy. It is also known from several other places in the world, including Gunma Prefecture in Japan and the Urucum mine in Mato Grosso do Sul, Brazil.
Rarity
Very rare
For collectors
## Quality criteria As a rare and microscopic mineral, its collector's value is low and mainly limited to specialized collectors of rare minerals (so-called "micromounts"). The most desirable specimens are those from the type locality (Cerchiara mine), with clearly visible, rich aggregates on a contrasting rock matrix, whose identity has been analytically confirmed.
Care and storage
## Cleaning Due to its softness and delicate, earthy form, mechanical or chemical cleaning is not recommended. If necessary, compressed air can be used to remove loose dust. Contact with water may damage the structure of delicate aggregates. ## What to avoid Avoid contact with water, acids, and all chemical agents. The mineral is very soft and susceptible to scratching and crumbling. It should be protected from ultrasound and high temperatures. ## Storage Manganiceladonite specimens are best stored in sealed, stable containers (collector's boxes) to protect them from mechanical damage, dust, and humidity. It is not suitable for open-air display.