Tamuraite

Chemical formula: Ir₅Fe₁₀S₁₆

Tamuraite is an extremely rare iridium iron sulfide, identified from a single grain found in Japan.

## Characteristics Tamuraite is a mineral known exclusively from a single, microscopic grain measuring approximately 20x30 micrometers. It was found within a heavy mineral concentrate. The grain had an irregular shape and was opaque, with a metallic luster and a black color. Due to its extreme rarity and the microscopic size of the only known occurrence, a full visual characterization of macroscopic specimens is not possible. ## History and Name The mineral was approved by the International Mineralogical Association (IMA) in 2010 under number IMA2010-058. Its name honors Tohru Tamura, director of the Nayoro Astronomical Observatory, for his contributions to the study of meteorites and platinum-group minerals. It was described by A. Kamei, S. V. Kovyazin, S. N. Britvin, and their colleagues.

Properties

Luster: Metallic
Streak: Black
Transparency: Opaque
Crystal system: Tetragonal

Diagnostic features

## Identification Identification of tamuraite is possible only through advanced laboratory techniques, such as electron microprobe (for chemical composition analysis) and electron diffraction (for determining crystal structure). It is not possible to identify it visually or in field conditions. ## Distinguishing from Similar Minerals Distinguishing it from other opaque, black sulfides or platinum-group minerals requires specialized chemical analysis, particularly to confirm the unique proportion of iridium, iron, and sulfur.

Geological environment

## Genesis Tamuraite was found in a heavy mineral concentrate originating from river sediments. Its primary source (parent rock) is unknown, but it is presumed to originate from ophiolite complexes (fragments of ancient oceanic crust) or ultramafic rocks, which are typical environments for platinum-group minerals. ## Mineral Associations The mineral was found in association with other platinum-group minerals, such as osmium, iridium, rutheniridosmine, as well as chromite and serpentine-group minerals. ## Localities The only confirmed occurrence worldwide (type locality) is in the alluvium of a river in the Nayoro area, Hokkaido Island, Japan.

Rarity

Extremely rare

For collectors

## Quality Criteria Tamuraite is not available on the collector's market. As a mineral known from a single microscopic grain, it is solely an object of scientific interest. Its value is purely scientific and related to its uniqueness as a new, approved mineral species.

Care and storage

## Cleaning Due to its microscopic size and uniqueness, any cleaning is not applied and would not be possible without the risk of material loss. ## What to Avoid Everything should be avoided – acids, chemicals, ultrasonics, temperature and humidity changes. The specimen is research material and should not be subjected to any actions other than analyses under controlled laboratory conditions. ## Storage The only known material is stored as a polished section in the scientific institution that described it, to protect it from damage and external factors.

Sources

IMA Mineral List (CNMNC)