Gladkovskyite

Chemical formula: Mn²⁺Tl¹⁺As³⁺₃S²⁻₆

Gladkovskyite is a rare manganese, thallium, and arsenic sulfide, distinguished by its dark cherry-red color and occurrence in gold deposits.

## Characteristics Gladkovskyite is a very rare mineral from the sulfosalt group, chemically classified as a manganese, thallium, and arsenic sulfide. It forms small, tabular or platy crystals, usually not exceeding 0.3 mm in size. It occurs as individual crystals or small aggregates intergrown with other minerals. Its most characteristic visual feature is its intense, dark cherry-red color. ## Physical Properties This mineral is relatively soft, with a Mohs hardness of 2-2.5. It is quite dense, with a density calculated from its chemical formula and unit cell parameters of 4.356 g/cm³. The crystals are transparent and exhibit a red streak. The fracture is uneven. ## Colors and Varieties Gladkovskyite occurs in a uniform, dark cherry-red color. No color varieties or commercial forms are known. ## History and Name The mineral was named in honor of the Russian geologist Nikolai Alekseevich Gladkovsky (1927-1981), a specialist in the geology of ore deposits. It was approved as a new mineral species by the International Mineralogical Association (IMA) in 2011. Its discovery was made in material from the Vorontsovskoe gold deposit in Russia. ## Uses Due to its extreme rarity and microscopic crystal size, gladkovskyite has no industrial applications. It is solely an object of scientific interest and a collector's item for specialized collectors of rare minerals.

Properties

Mohs hardness
2-2.5
Streak
Red
Density
4.356
Fracture
Irregular/Uneven
Transparency
Transparent
Crystal system
Trigonal

Diagnostic features

## Identification Identification of gladkovskyite under amateur conditions is practically impossible due to the microscopic size of the crystals and similarity to other red sulfosalts. Key features include its dark cherry-red color, red streak, and co-occurrence with other thallium and arsenic minerals in a specific geological environment. Definitive identification requires advanced analytical methods, such as X-ray microanalysis (EDS/WDS). ## Distinguishing from Similar Minerals Gladkovskyite can be confused with other red, transparent sulfosalts, such as realgar, lorandite, or parapierrotite. Realgar is usually brighter and more orange-red, and also unstable in light. Lorandite has perfect cleavage. Final differentiation requires chemical composition analysis, confirming the presence of manganese, thallium, and arsenic in specific proportions. ## Crystal Forms Gladkovskyite forms very small, thin, tabular or platy crystals, often with a hexagonal outline. They typically occur as single, dispersed crystals on the surface of other minerals or in their fissures.

Geological environment

## Genesis Gladkovskyite is a hydrothermal mineral. It forms in the final stages of crystallization in Carlin-type gold deposits, rich in arsenic, sulfur, and thallium. It crystallizes at low temperatures from hydrothermal solutions in caverns and fractures of carbonate rocks. ## Mineral Associations This mineral co-occurs with other rare arsenic and thallium sulfosalts. In its type locality, it was found in association with parapierrotite, wurtzite, realgar, orpiment, getchellite, stibnite, pyrite, as well as calcite and quartz. ## Localities The only confirmed occurrence of gladkovskyite worldwide is its type locality - the Vorontsovskoe gold deposit, located in the Serov district of the Sverdlovsk Oblast in Russia.

Rarity

Extremely rare

For collectors

## Quality Criteria The quality of a gladkovskyite specimen is primarily determined by the size and quality of the crystals. The most desirable specimens are those with well-formed, sharp, undamaged crystals of an intense, dark red color. The abundance of crystals on the matrix and their aesthetic arrangement are also highly valued. Contrast with a light matrix rock (e.g., quartz or calcite) enhances visual appeal. ## Popular Localities The only source of specimens is the Vorontsovskoe deposit in Russia. Material from this locality is extremely difficult to acquire and appears on the collector's market sporadically.

Care and storage

## Cleaning Specimens containing gladkovskyite, due to their microscopic size and delicacy, should generally not be mechanically cleaned. If absolutely necessary, compressed air (from a safe distance) can be used to remove loose dust particles. Avoid contact with water and chemicals. ## What to Avoid Avoid contact with any acids and chemical agents that may react with sulfides. The mineral is soft and susceptible to scratching. Protect it from high temperatures and direct, intense sunlight, which can affect its properties over time. ## Storage Specimens should be stored in stable conditions, preferably in a sealed "micromount" box, to protect them from dust, mechanical damage, and sudden changes in humidity. Display should be away from sources of vibration and direct light.

External references

Sources

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