Chlorartinite

Chemical formula: Mg₂CO₃Cl(OH)·₂.₅H₂O

Chlorartinite is a rare, hydrated basic magnesium chloride-carbonate, forming white, silky aggregates of acicular crystals.

## Characteristics Chlorartinite is a mineral from the carbonate group, chemically classified as a hydrated basic magnesium chloride-carbonate. It occurs as aggregates of fine, acicular or fibrous crystals, which often form silky-looking aggregates, rosettes, or coatings. Individual crystals are usually too small to be seen with the naked eye, and the material tends to be brittle. ## Physical Properties This mineral is characterized by low hardness, approximately 2 on the Mohs scale, which means it is very soft. It has a silky luster, resulting from its fibrous structure. It is translucent to opaque. Its density is low, approximately 2.03 g/cm³. ## Colors and Varieties Chlorartinite is typically white, snow-white, or colorless. No colored varieties are distinguished. ## History and Name The mineral's name refers to its chemical composition – the presence of chlorine (chloro-) and its association with the mineral artinite (-artinite), with which it often coexists and is morphologically similar. It was described as a new mineral in 2011 by Daria L. Belakovskiy, Igor V. Pekov, Oleg V. Karyakin, Dmitry I. Belakovskiy, and Elena G. Panova. The type locality (locus typicus) is the Kopeisk mine in the Chelyabinsk Oblast, Southern Urals, Russia. ## Uses Chlorartinite has no industrial applications. It is solely an object of interest for collectors specializing in rare minerals and a subject of scientific research.

Properties

Mohs hardness: 2
Luster: Silky
Streak: White
Density: 2.03
Cleavage: None
Fracture: Uneven
Transparency: Translucent to opaque
Crystal system: Monoclinic

Diagnostic features

## Identification Chlorartinite can be identified by its characteristic, silky aggregates composed of very fine, acicular or fibrous crystals. Its white color, low hardness (approximately 2), and coexistence with other magnesium minerals in specific environments are key identifying features. ## Distinguishing from Similar Minerals Chlorartinite is visually very similar to artinite, with which it often coexists. Artinite (Mg₂(CO₃)(OH)₂·3H₂O) has a similar appearance (white, acicular aggregates) and physical properties. Reliable distinction between these two minerals is almost exclusively possible using advanced analytical methods, such as X-ray diffraction (XRD) or chemical analysis (EDS/WDS). ## Crystal Forms This mineral forms elongated, acicular or hair-like crystals, typically up to 1 mm long and only a few micrometers thick. These crystals combine into tangled, fibrous masses, spherical aggregates, rosettes, and thin coatings on rock surfaces.

Geological environment

## Genesis Chlorartinite is a secondary mineral that forms as a result of low-temperature processes. In the type locality in the Urals, it formed as an alteration product of rocks in mine dumps, resulting from the reaction of magnesium-rich waters with solutions containing chloride and carbonate ions. It is a typical mineral of weathering zones of ultramafic rocks (serpentinites) or magnesium-rich hydrothermal formations. ## Mineral Associations It most commonly coexists with artinite, hydromagnesite, pyroaurite, iowaite, magnesite, and brucite. ## Localities The most important and best-documented locality, which is also the type locality, is the coal mine dumps in Kopeisk, in the Chelyabinsk Coal Basin in the Southern Urals, Russia. It has also been identified in mines near the city of Ozersk in the same region. Outside Russia, its occurrence is very limited and poorly documented.

Rarity

Very rare

For collectors

## Quality Criteria Specimens with well-formed, fluffy aggregates of acicular crystals, forming aesthetic rosettes or spherical forms, are most valued by collectors. Contrast with the rock matrix and the absence of damage to the delicate fibers are important. Due to its rarity, any well-documented specimen, even a small one, holds value for specialized collectors. ## Popular Localities The only source of specimens of collector's significance is the Chelyabinsk region in the Southern Urals, Russia, particularly the dumps of the Kopeisk mine.

Care and storage

## Cleaning Chlorartinite specimens are extremely delicate and brittle. Mechanical cleaning should be avoided. If absolutely necessary, a very careful stream of compressed air can be used from a safe distance to remove loose dust. Contact with water is inadvisable due to the risk of dissolution or damage to the delicate fibers. ## What to Avoid Contact with water, acids, and other chemicals must be strictly avoided. The mineral is very soft, susceptible to scratches and mechanical damage. It should be protected from vibrations, impacts, and abrasion. It should not be heated or exposed to ultrasound. ## Storage It is recommended to store specimens in sealed, padded "micromount" boxes to protect them from dust, moisture, and physical damage. Display should be in a closed cabinet, away from sources of vibration.

Sources

IMA Mineral List (CNMNC)