Yagiite

Chemical formula: NaMg₂(AlMg₂Si₁₂)O₃₀

Yagiite is an extremely rare mineral of the osumilite group, found exclusively in the Colomera iron meteorite, occurring as colorless, hexagonal crystals.

## Characteristics Yagiite is a sodium, magnesium, and aluminum silicate belonging to the osumilite group. It forms small, hexagonal, tabular or prismatic crystals, usually not exceeding 0.1 mm in diameter. It occurs as single grains alongside other minerals within silicate enclaves in the iron meteorite. It is colorless and transparent to translucent, which makes its identification difficult without specialized equipment. ## Physical Properties The mineral is characterized by a hardness in the range of 5-6 on the Mohs scale. Its luster is vitreous. Due to its extreme rarity and microscopic crystal size, many of its physical properties, such as density or cleavage, have not been precisely determined. ## Colors and Varieties Yagiite is colorless. No colored or commercial varieties are known. ## History and Name The mineral was discovered in 1968 in the Colomera iron meteorite, which fell in Spain. Its name honors Kenzo Yagi (1914-2008), a Japanese petrologist and mineralogist from Hokkaido University, for his contributions to the study of minerals of the osumilite group.

Properties

Mohs hardness: 5-6
Luster: Vitreous
Density: 0
Transparency: Translucent
Crystal system: Hexagonal

Diagnostic features

## Identification Identification of yagiite is possible only using advanced analytical techniques, such as electron microprobe (EDS/WDS) or X-ray diffraction (XRD), due to its microscopic size and lack of characteristic visual features. It occurs as colorless, hexagonal crystals in silicate enclaves of the Colomera meteorite. ## Distinguishing from similar minerals Visually, it is indistinguishable from other colorless minerals co-occurring in the meteorite, such as diopside, whitlockite, or plagioclase. Definitive differentiation requires analysis of chemical composition and crystal structure. ## Crystal forms It forms hexagonal, tabular or short prismatic crystals, occurring as single grains.

Geological environment

## Genesis Yagiite is an extraterrestrial mineral. It formed as a result of crystallization processes within silicate inclusions inside an iron meteorite (IIE group octahedrite) during its formation in space. ## Mineral associations It co-occurs with other minerals found in the Colomera meteorite, such as diopside, plagioclase (albite), whitlockite, tridymite, quartz, graphite, and native metals - kamacite and taenite. ## Localities The only confirmed locality of yagiite in the world is its type locality - the Colomera meteorite, found near the town of Colomera in the province of Granada, Andalusia (Spain).

Rarity

Extremely rare

For collectors

## Quality criteria As a mineral available exclusively as microscopic inclusions in a meteorite, its collector value is inextricably linked to the value of the Colomera meteorite specimen itself. The presence of well-formed, analytically identifiable yagiite crystals in a studied sample enhances its appeal. These specimens almost exclusively end up in institutional and research collections. ## Popular localities The only source of yagiite is the Colomera meteorite, so there are no "popular localities" in the collector's sense. Fragments of this meteorite are extremely rare on the market.

Care and storage

## Cleaning Due to its microscopic size and occurrence in a delicate matrix, specimens containing yagiite should not be cleaned mechanically or chemically. Any attempts at cleaning may damage the mineral or its surroundings. ## What to avoid Avoid contact with any chemicals, ultrasonic cleaning, and extreme temperature changes. The specimen should be protected from shocks and vibrations. ## Storage Specimens containing yagiite, being fragments of a meteorite, are best stored in stable conditions, in a padded "perky box" or display case, away from dust, moisture, and direct sunlight.