Bezsmertnovite

Chemical formula: (Au,Ag)<sub>4</sub>Cu(Te,Pb)

Bezsmertnovite is a rare, metallic telluride of gold, silver, copper, and lead, forming small grains embedded in rock.

## Characteristics Bezsmertnovite is a very rare mineral from the telluride group, characterized by a complex chemical composition including gold, silver, copper, lead, and tellurium. It occurs as very small, irregular grains or aggregates, usually not exceeding 0.2 mm in size. Its specimens are most often embedded in other minerals, making isolated crystals virtually nonexistent. It has a metallic appearance and a creamy-yellow color with a pinkish hue. ## Physical Properties This mineral is characterized by a metallic luster. Due to the microscopic size of the grains, many of its physical properties, such as hardness, density, cleavage, or fracture, have not been precisely determined. It is an opaque mineral. ## Colors and Varieties Bezsmertnovite has a characteristic creamy-yellow color, often with a pinkish hue. In reflected light, it may exhibit weak pleochroism from creamy-white to slightly pinkish. No varieties have been distinguished. ## History and Name The mineral was discovered in the Aginsk (Aginskoe) deposit in Kamchatka, Russia. Its name, approved by IMA in 1978, honors the Russian mineralogist Marianna Sergeevna Bezsmertnaya (1915-1991) and her husband Vladimir Vasilievich Bezsmertny (1912-2002), researchers of ore deposits, including gold tellurides. ## Applications Bezsmertnovite has no industrial application. Its significance is purely scientific and collectible, as a very rare telluride of noble metals.

Properties

Mohs hardness
3.5
Luster
Metallic
Streak
Gray
Density
16.6
Transparency
Opaque
Crystal system
Orthorhombic

Diagnostic features

## Identification Identification of bezsmertnovite is only possible using advanced laboratory methods, such as chemical composition analysis (EDS/WDS) with an electron microprobe and X-ray diffraction (XRD) analysis. Visually, in a polished section under a microscope, it can be recognized by its creamy-yellow color with a pinkish hue and metallic luster. ## Distinguishing from Similar Minerals It can be confused with other rare gold tellurides, such as bogdanovite, bilibinskite, or krennerite. Definitive differentiation requires chemical analysis to show the presence and proportions of gold, silver, copper, lead, and tellurium, characteristic of bezsmertnovite. ## Crystal Forms Bezsmertnovite forms exclusively anhedral (irregular) grains and aggregates, typically less than 0.2 mm in size. No well-formed crystals have been observed.

Geological environment

## Genesis Bezsmertnovite is a hydrothermal mineral. It forms in the final stages of crystallization in tellurium-rich volcano-plutonic complexes under low-temperature conditions. ## Mineral Associations It most often co-occurs with other tellurides, such as bilibinskite, bogdanovite, as well as native gold, pyrite, chalcopyrite, and quartz. It frequently forms intergrowths with other minerals from the bilibinskite group. ## Localities The most important and type locality is the Aginsk (Aginskoe) gold deposit on the Kamchatka Peninsula in Russia. This is the only confirmed and well-documented locality for this mineral in the world.

Rarity

Very rare

For collectors

## Quality Criteria The quality of a bezsmertnovite specimen depends solely on the richness and size of the grains visible under a microscope within the host rock. Since this mineral does not form aesthetic crystals, its collectible value is purely scientific and related to its rarity. The best specimens are those with well-documented locality information and analytically confirmed mineral identity. ## Popular Localities The only source of bezsmertnovite specimens is its type locality – the Aginsk deposit in Kamchatka, Russia. All specimens available on the collector's market originate from this single location.

Care and storage

## Cleaning Bezsmertnovite specimens, due to their microscopic nature and occurrence as inclusions in other minerals, are generally not cleaned. Any attempt at mechanical or chemical cleaning could irrevocably damage the delicate grains. ## What to Avoid Avoid contact with chemicals, acids, and ultrasound. Do not heat specimens. Temperature and humidity changes do not significantly affect the mineral itself, but they can damage the host rock. ## Storage Bezsmertnovite specimens are best stored under stable conditions in their original host rock, in a sealed "micromount" box, to protect them from dust and mechanical damage. A label with precise locality information is crucial.

External references

Sources

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