Thalhammerite

Chemical formula: Pd₉Ag₂Bi₂S₄

Thalhammerite is a very rare palladium, silver, and bismuth sulfide, forming tiny, metallic grains with a yellowish tint.

## Characteristics Thalhammerite is an extremely rare sulfide mineral, composed of palladium, silver, bismuth, and sulfur. It occurs as very small, anhedral (irregularly shaped) grains, typically not exceeding 100 micrometers in size. It is observed in polished sections under a microscope, where it reveals its metallic character. Its color in reflected light is described as light yellow to yellowish-brown. ## Physical Properties As an opaque mineral, thalhammerite is characterized by a strong metallic luster. Its density is very high, at 9.72 g/cm³, which is typical for minerals containing heavy metals such as palladium and bismuth. Hardness has not been precisely measured due to the small size of the grains. ## History and Name The mineral was named in honor of Oskar A.R. Thalhammer (born 1955), an Austrian geologist and professor at the University of Leoben, in recognition of his contributions to the study of platinum-group element deposits. It was approved as a new mineral species by the International Mineralogical Association (IMA) in 2018 (IMA2018-012). The type locality where thalhammerite was first identified is the Komsomolsky mine in the Norilsk region, Russia. ## Applications Due to its extreme rarity and microscopic size, thalhammerite has no industrial applications. Its significance is purely scientific and collectible, being an object of interest for specialized institutions and collectors of systematic minerals and micromounts.

Properties

Luster
Metallic
Density
9.72
Transparency
Opaque
Crystal system
Tetragonal

Diagnostic features

## Identification Identification of thalhammerite is possible only with advanced laboratory techniques, such as reflected light ore microscopy and chemical analysis using an electron microprobe (EDS/WDS). Characteristic features in the microscopic image include its light yellow color, strong metallic luster, and co-occurrence with other sulfides and platinum-group minerals. ## Distinguishing from Similar Minerals Under the microscope, it can be confused with other yellow sulfides, such as chalcopyrite, pentlandite, or other platinum-group minerals. Definitive differentiation requires chemical analysis, which will reveal the unique combination of palladium, silver, bismuth, and sulfur. ## Crystal Forms Thalhammerite forms exclusively anhedral, irregular grains embedded in the matrix of other minerals, mainly copper and iron sulfides. It has not been observed in the form of well-developed crystals.

Geological environment

## Genesis Thalhammerite forms as a result of magmatic processes associated with the crystallization of sulfide copper-nickel deposits. It crystallizes in the late stages from a residual, noble metal-rich sulfide phase, under high-temperature conditions. ## Mineral Associations This mineral occurs in close association with other sulfides and platinum-group minerals. In the type locality, it was found in association with chalcopyrite, talnakhite, mooihoekite, cubanite, polarite, mayakite, atokite, rustenburgite, palladoarsenide, native bismuth, and gold-silver alloys. ## Localities The only confirmed occurrence of thalhammerite in the world is its type locality – the Komsomolsky mine within the Talnakh copper-nickel deposit, on the Taimyr Peninsula in Russia.

Rarity

Extremely rare

For collectors

## Quality Criteria As a microscopic mineral, thalhammerite is not evaluated according to typical criteria such as crystal size or form. The value of a specimen lies in its confirmed authenticity and the richness of the mineral association visible in the polished section or sample. The most valuable specimens are those from the type locality, with accurately documented chemical analysis. ## Popular Localities The only source of specimens is the Komsomolsky mine in the Norilsk region, Russia. Research and collector material from this location is extremely difficult to obtain.

Care and storage

## Cleaning Thalhammerite specimens occur as microscopic inclusions in other minerals and are usually stored as polished sections or in special micromount boxes. They do not require cleaning. If necessary, a dusty polished surface can be wiped with a very soft, dry microfiber cloth. ## What to Avoid Avoid contact with any chemicals, acids, or cleaning agents. Ultrasonic cleaning is not recommended. Polished sections should be protected from scratching, impacts, and drops. ## Storage Microscopic specimens should be stored in dedicated "micromount" boxes, protecting them from dust and mechanical damage. Polished sections are best kept in special containers or envelopes to prevent scratching their surfaces.

External references

Sources

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