Vymazalováite
Chemical formula: Pd₃Bi₂S₂
Vymazalováite is a very rare palladium-bismuth sulfide, forming microscopic, metallic grains in association with other ore minerals.
Properties
- Mohs hardness
- 3.5
- Luster
- Metallic
- Streak
- Gray
- Density
- 9.25
- Cleavage
- None
- Fracture
- Uneven
- Transparency
- Opaque
- Crystal system
- Isometric
Diagnostic features
## Identification Identification of vymazalováite is possible only through advanced laboratory techniques. The basis is analysis in reflected light using an ore microscope, where its characteristic creamy-white color, strong metallic luster, and anisotropy are observed. Final confirmation requires chemical analysis using an electron microprobe (EDS/WDS) to determine the composition (presence of palladium, bismuth, and sulfur in appropriate proportions) and X-ray diffraction (XRD) to confirm the crystal structure. ## Distinguishing from Similar Minerals This mineral can be confused with other microscopic sulfides and metal alloys, such as other platinum-group minerals (PGM), native bismuth, or argentopentlandite. Differentiation is based on subtle differences in color and reflectance, and above all, on precise chemical composition analysis. ## Crystal Forms Vymazalováite occurs as anhedral, irregular grains and aggregates. No euhedral, well-formed crystals have been observed.
Geological environment
## Genesis Vymazalováite is a hydrothermal mineral. It forms in ore deposits as a result of crystallization from solutions rich in palladium, bismuth, and sulfur. At the type locality (O'Toole), it is associated with serpentinized ultramafic rocks (komatiites), where its formation is linked to hydrothermal processes occurring at temperatures below 300°C. ## Mineral Associations This mineral co-occurs with a wide range of other ore minerals. At the type locality, it was found in association with chalcopyrite, pentlandite, pyrite, millerite, heazlewoodite, native bismuth, as well as other rare minerals such as oosterboschite, sudburyite, sobolevskite, michenerite, froodite, insizwaite, and argentopentlandite. ## Localities Confirmed occurrences of vymazalováite are extremely limited. Besides the type locality at the O'Toole mine (Serranía de Ronda, Malaga province, Spain), it has also been identified in the Kalatongke nickel-copper deposit in the Xinjiang autonomous region of China.
Rarity
Extremely rare
For collectors
## Quality Criteria Vymazalováite is not a mineral available on the collector's market in the form of macroscopic specimens. Its value is purely scientific. In a research context, the "quality" of a specimen refers to the size of the grains (the larger, the better for analysis), their purity (lack of intergrowths with other phases), and the richness of the mineral association on a given microscopic polished section. These specimens are found exclusively in the collections of scientific institutions and museums. ## Popular Localities The only source of material that may enter institutional collections are the two known localities: the O'Toole mine in Spain and the Kalatongke deposit in China. Material from these sites is extremely difficult to obtain.
Care and storage
## Cleaning Due to its microscopic nature and occurrence as inclusions in polished sections, vymazalováite specimens do not require and are not amenable to standard cleaning. Microscopic preparations (polished sections) should be protected from dust and scratches. ## What to Avoid Avoid contact with chemicals, acids, and any abrasive agents that could damage the delicate, polished surface of the section and destroy the microscopic mineral grains. ## Storage Microscopic sections containing vymazalováite should be stored in specialized boxes, in a dry place, to prevent the oxidation of sulfides and tarnishing of the polished surface.