Magnesiocanutite

Chemical formula: Na◻Mn²⁺Mg₂[As⁵⁺O₄]₂[As⁵⁺O₂(OH)₂]

Magnesiocanutite is a very rare arsenate of the alluaudite group, distinguished by its pale, pinkish color and occurrence as tiny crystals.

## Characteristics Magnesiocanutite is a hydrated sodium, manganese, and magnesium arsenate belonging to the alluaudite group. It forms small, tabular or bladed crystals, usually not exceeding 1 mm in length. It occurs as radial or irregular aggregates. It is a transparent mineral with a vitreous luster. ## Physical Properties This mineral is characterized by a relatively low hardness of 2.5 on the Mohs scale, meaning it can be scratched with a fingernail. Its density is quite high, approximately 3.96 g/cm³. It exhibits distinct cleavage in two directions, and its fracture is splintery. ## Colors and Varieties The typical coloration of magnesiocanutite ranges from pale pink and pinkish to pale brownish-pink. No distinct color varieties or commercial varieties have been identified. ## History and Name The mineral's name refers to its chemical composition – the dominance of magnesium (magnesio) – and honors the Chilean mineralogist and mining engineer Claudio Canut de Bonfils (canutite). It was officially recognized as a new mineral species by the International Mineralogical Association (IMA) in 2018 (IMA2018-058). The type locality is the Torrecillas mine in Chile. ## Uses Magnesiocanutite, as an extremely rare mineral occurring in microscopic crystals, has no industrial applications. It is solely of scientific and collector's interest.

Properties

Mohs hardness
2.5
Luster
Vitreous
Streak
Very pale pink
Density
3.957
Cleavage
{010} and {101}
Fracture
Splintery
Transparency
Transparent
Crystal system
Monoclinic

Diagnostic features

## Identification Amateur identification of magnesiocanutite is practically impossible. It requires advanced analytical methods, such as X-ray diffraction (XRD) and chemical spectroscopy (EDS/WDS). Preliminary identification is based on its pink color, co-occurrence with other rare arsenates, and characteristic locality. ## Distinguishing from Similar Minerals It can be confused with other pink arsenates of the alluaudite group, such as canutite or manganocanutite, from which it differs by the dominance of magnesium in its chemical composition. Visual differentiation from these minerals without specialized analysis is impossible. ## Crystal Forms Crystals are typically very small, tabular or bladed, flattened parallel to the {010} plane. They form radial aggregates or irregular clusters on the surface of the host rock.

Geological environment

## Genesis It is a secondary mineral formed as a result of hydrothermal processes or weathering in the oxidation zones of polymetallic deposits rich in arsenic. In its type locality, it formed from the oxidation of primary sulfides and arsenides. ## Mineral Associations Magnesiocanutite co-occurs with other rare arsenate minerals such as canutite, manganocanutite, lavendulan, erythrite, annabergite, pharmacolite, as well as quartz and gypsum. ## Localities The only confirmed and described occurrence of magnesiocanutite in the world is its type locality – the Torrecillas mine, located near Salar Grande, in the Iquique Province of the Tarapacá Region in northern Chile.

Rarity

Extremely rare

For collectors

## Quality Criteria The quality of collector specimens primarily depends on the richness and aesthetics of the crystal aggregates on the rock matrix. The most valued specimens are those with well-formed, intensely colored (for this mineral) crystals, forming visually attractive clusters. Contrast with the matrix and the presence of associated minerals also increase the specimen's value. ## Popular Localities All known specimens originate from a single location in the world – the Torrecillas mine in Chile. This is the sole source of this mineral for collectors and scientific institutions.

Care and storage

## Cleaning Specimens should be cleaned very carefully, using only a soft brush to remove dust. Due to its low hardness and the presence of arsenates, contact with water and any chemical agents should be avoided. Wet cleaning is absolutely not recommended. ## What to Avoid The mineral is very brittle and soft, so it should be protected from impacts, scratching, and vibrations. Contact with acids, detergents, and other chemicals should be avoided. It should not be heated or exposed to prolonged moisture. ## Storage It is recommended to store specimens in stable, sealed "micromount" containers that protect against dust, mechanical damage, and sudden changes in humidity. Display should be away from sources of vibration and direct sunlight.

External references

Sources

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