Manganobadalovite

Chemical formula: NaNaMn²⁺(MgFe³⁺)(As⁵⁺O₄)₃

Manganobadalowite is a very rare arsenate from the alluaudite group, distinguished by its complex chemical composition containing sodium, manganese, magnesium, and iron.

## Characteristics Manganobadalowite is an arsenate belonging to the alluaudite group. This mineral forms very small, granular aggregates up to 0.2 mm in size. Individual grains are usually anhedral (lacking their own crystal faces) and rarely exceed 50 micrometers. Due to the small size of the crystals, visual characteristics visible to the naked eye are difficult to determine. ## Physical Properties Manganobadalowite crystals exhibit a vitreous luster. The mineral is brittle. Its Mohs hardness is 3.5, and its density calculated from crystallographic data is 4.23 g/cm³. ## Colors and Varieties The mineral is dark brown to black, with a characteristic reddish-brown internal reflection in transmitted light. The streak is light brown. No varieties have been distinguished. ## History and Name The mineral's name honors Pavel Badanov (born 1970), a Russian mineral collector from Moscow, who specializes in minerals from volcanic fumaroles, including the type locality for manganobadalowite. The prefix "mangano-" refers to the dominance of manganese (Mn²⁺) in one of the structural positions. The mineral was approved by the International Mineralogical Association (IMA) in 2018 under number IMA2018-016. It was described by Russian mineralogists led by Igor V. Pekov.

Properties

Mohs hardness: 3-0
Color: red, brownish-red and orange-to-orange-yellow and honey-colored.
Luster: Vitreous
Streak: white-to-pale-yellowish
Density: 4.108
Cleavage: noticeable cleavage in one direction
Fracture: Irregular/Uneven
Transparency: Transparent,Translucent
Crystal system: Monoclinic

Diagnostic features

## Identification Identification of manganobadalowite is possible only through advanced analytical methods, such as Raman spectroscopy, electron microprobe (EDS/WDS), and X-ray diffraction (XRD). The dark brown to black color, reddish-brown internal reflections, and light brown streak are auxiliary features but insufficient for certain identification. ## Distinguishing from Similar Minerals This mineral is visually indistinguishable from other dark, fine-grained arsenates of the alluaudite group, such as badanovite, ferromanganobadalowite, or magnesio-alluaudite. Differentiation requires precise chemical analysis to determine the dominant elements in specific crystallographic positions. ## Crystal Forms Manganobadalowite crystals occur as anhedral (xenomorphic) grains forming small, granular aggregates. No well-formed, euhedral crystals have been observed.

Geological environment

## Genesis Manganobadalowite forms in a unique environment of high-temperature (450–600°C) volcanic fumaroles. It crystallizes in the exhalation zone, where hot, arsenic-rich volcanic gases react with surrounding rocks. ## Mineral Associations This mineral coexists with other rare arsenates and oxides formed under similar conditions. At the type locality, it was found in association with hematite, tenorite, cassiterite, sylvite, halite, arcanite, langbeinite, anhydrite, sanidine, badanovite, nikolaevite, udinaite, alarsite, arsenatrotitanite, erythrite, annabergite, pharmacolite, and picropharmacolite. ## Localities The only confirmed occurrence of manganobadalowite in the world is its type locality - the Arsenatnaya fumarole, located on the second cinder cone of the Northern Breakthrough of the Great Tolbachik Fissure Eruption on Tolbachik volcano, Kamchatka, Russia.

Rarity

Extremely rare

For collectors

## Quality Criteria As a microscopic mineral, the collector's value of manganobadalowite is not based on aesthetics but on its extreme rarity and scientific significance. The most valuable specimens are those where the mineral has been unequivocally identified analytically and coexists with other rare arsenates from this locality. The abundance of material (number of grains) on the rock matrix increases the specimen's value.

Care and storage

## Cleaning Due to its extreme rarity, brittleness, and small grain size, mechanical cleaning is not recommended. Specimens should be analyzed and preserved exclusively under laboratory conditions. ## What to Avoid Avoid contact with chemicals, especially acids, which can react with arsenates. Also avoid ultrasound, high temperatures, and moisture. ## Storage Specimens should be stored under stable conditions, in specialized, sealed micromount containers, protecting them from dust, shocks, and changes in humidity.

External references

https://www.mindat.org/min-55097.html