Tsikourasite

Q: How to identify Tsikourasite?

## Identification Identification of tsikourasite is impossible without advanced laboratory techniques. It requires analysis in reflected light under a polarizing microscope and confirmation of chemical composition using an electron microprobe (EDS/WDS). In reflected light, it is silvery-white and exhibits weak anisotropy. ## Distinguishing from similar minerals It can be confused with other metallic minerals found in ultramafic rocks, such as other phosphides (e.g., niquelfosfide), sulfides, or platinum-group metal alloys. Definitive differentiation is only possible based on chemical analysis.

Q: Where does this mineral come from Tsikourasite?

## Genesis Tsikourasite forms under specific conditions in ultramafic rocks that are part of ophiolite complexes. Its genesis is related to processes occurring in the Earth's upper mantle, where, in a strongly reducing environment, with the presence of phosphorus-rich fluids, metal phosphides crystallize within chromitite massifs. ## Mineral associations This mineral occurs in paragenesis with chr

Q: How to care for Tsikourasite?

## Cleaning Specimens containing tsikourasite (typically polished rock samples or thin sections) should only be cleaned with compressed air to remove dust. Any wet or mechanical cleaning should be avoided. ## What to avoid Contact with chemicals, acids, detergents, and ultrasound must be strictly avoided. Specimens should be protected from scratching, impact, and sudden temperature changes. They should not be exposed to moisture. ## Storage Specimens containing tsikourasite, most often in the fo

Chemical formula: Mo₃Ni₂P₁+x (x < ₀.₂₅)

Tsikourasite is an extremely rare, newly discovered molybdenum and nickel phosphide, identified as microscopic grains in chromitites.

## Characteristics Tsikourasite is a metallic, opaque mineral with a silvery-white color and metallic luster. It has only been identified in the form of very small, anhedral (not exhibiting its own crystal faces) grains, not exceeding 300 micrometers in size. These grains occur as inclusions within much larger chromite crystals. Due to its microscopic size and occurrence as inclusions, its macroscopic features are unknown. ## Physical Properties Due to the microscopic size of the grains, most physical properties, such as hardness, density, cleavage, or fracture, have not been determined. The mineral is opaque and has a metallic luster. ## History and Name Tsikourasite was officially recognized as a new mineral by the International Mineralogical Association (IMA) in 2022 (IMA2022-045). The name honors Prof. Basilios Tsikouras from the Cyprus University of Technology, in recognition of his contribution to the study of ophiolitic rocks, where the discovery was made. The mineral was discovered in the Othrys chromite mine in Greece. ## Uses Tsikourasite has no commercial or industrial application. Its significance is purely scientific and collector-oriented, as an extremely rare, newly described mineral species.

Properties

Luster: Metallic
Transparency: Opaque
Crystal system: Hexagonal

Diagnostic features

## Identification Identification of tsikourasite is impossible without advanced laboratory techniques. It requires analysis in reflected light under a polarizing microscope and confirmation of chemical composition using an electron microprobe (EDS/WDS). In reflected light, it is silvery-white and exhibits weak anisotropy. ## Distinguishing from similar minerals It can be confused with other metallic minerals found in ultramafic rocks, such as other phosphides (e.g., niquelfosfide), sulfides, or platinum-group metal alloys. Definitive differentiation is only possible based on chemical analysis. ## Crystal forms Tsikourasite occurs exclusively as anhedral, irregular grains, usually with rounded contours, as inclusions in chromite.

Geological environment

## Genesis Tsikourasite forms under specific conditions in ultramafic rocks that are part of ophiolite complexes. Its genesis is related to processes occurring in the Earth's upper mantle, where, in a strongly reducing environment, with the presence of phosphorus-rich fluids, metal phosphides crystallize within chromitite massifs. ## Mineral associations This mineral occurs in paragenesis with chromite (as inclusions within it), as well as with other rare phosphides, such as niquelfosfide, and probably with platinum-group minerals. ## Localities The only confirmed occurrence (type locality) of tsikourasite in the world is the Othrys chromite mine, located in the ophiolite massif of the same name in the Phthiotis region, central Greece.

Rarity

Extremely rare

For collectors

## Quality criteria The quality of a tsikourasite specimen is determined solely by its scientific and documentary value. Since the mineral is invisible to the naked eye, collector specimens are most often polished thin sections or fragments of the host rock (chromitite) with a precisely studied and marked location of the microscopic grain. Cotype specimens from the original find are the most valuable. ## Popular localities The only source of specimens is the type locality in Greece. Availability on the collector's market is practically zero and limited to scientific institutions and specialized systematic collections.

Care and storage

## Cleaning Specimens containing tsikourasite (typically polished rock samples or thin sections) should only be cleaned with compressed air to remove dust. Any wet or mechanical cleaning should be avoided. ## What to avoid Contact with chemicals, acids, detergents, and ultrasound must be strictly avoided. Specimens should be protected from scratching, impact, and sudden temperature changes. They should not be exposed to moisture. ## Storage Specimens containing tsikourasite, most often in the form of professional preparations (thin sections), should be stored in specialized microscope slide boxes or padded "perky boxes", in a dry place with stable temperature, away from dust.

Sources

IMA Mineral List (CNMNC)