Abuite
Chemical formula: CaAl<sub>2</sub>(PO<sub>4</sub>)<sub>2</sub>F<sub>2</sub>
Abuite is an extremely rare phosphate mineral, first described in Japan, forming colorless, microscopic grains.
Properties
- Mohs hardness
- 5
- Luster
- Vitreous
- Streak
- White
- Density
- 3.23
- Fracture
- Uneven
- Transparency
- Transparent
- Crystal system
- Tetragonal
Diagnostic features
## Identification Identification of abuite is impossible based on visual characteristics alone. Its colorlessness, microscopic size, and lack of well-formed crystals make it indistinguishable from many other minerals in field and collection conditions. Certain identification requires advanced analytical techniques, such as X-ray diffraction (XRD) or X-ray microanalysis (EDS). ## Distinguishing from Similar Minerals It can be confused with many common and rare minerals found in pegmatites, such as quartz, apatite, or other colorless phosphates (e.g., wardite, crandallite). A key diagnostic clue is its co-occurrence with a characteristic mineral assemblage in a typical locality. Final distinction is possible only by laboratory methods. ## Crystal Forms Abuite does not form well-developed crystals. It occurs exclusively as anhedral, i.e., irregular grains, which coalesce into small, compact aggregates.
Geological environment
## Genesis Abuite is a hydrothermal mineral, crystallizing in the late stage of granite pegmatite evolution. It forms in small voids and fractures within the pegmatite dike. ## Mineral Associations This mineral occurs in association with other, often rare, phosphates. Its typical associated minerals include goyazite, morinite, minerals of the childrenite-eosphorite series, wardite, wavellite, crandallite, minerals of the apatite group, as well as montebrasite, quartz, albite, and muscovite. ## Localities The only confirmed occurrence of abuite in the world is its type locality – the Hinomaru-Nago mine, located in Sakihama, Ibaraki Prefecture, Japan.
Rarity
Extremely rare
For collectors
## Quality Criteria For such a rare microscopic mineral, the main criterion for value is the certainty of identification, confirmed by a reputable laboratory. Collectors value specimens where abuite aggregates are as numerous as possible and clearly visible against the rock matrix. The presence of other rare associated minerals on the same specimen adds significant value. ## Popular Localities The only source of collectible specimens is the type locality – the Hinomaru-Nago mine in Japan. Specimens from this location are highly sought after by collectors specializing in rare minerals and micromounts.
Care and storage
## Cleaning Abuite specimens, being microscopic and embedded in a rock matrix, should not be cleaned mechanically or chemically. Fine dust can be removed with a gentle stream of compressed air. Avoid contact with water and any detergents. ## What to Avoid Ultrasonic cleaners, which could destroy delicate aggregates, should be absolutely avoided. The mineral should be protected from contact with acids and other chemicals. Its reactions to light or temperature are not known, but standard caution and avoidance of extreme conditions are recommended. ## Storage The safest storage method is a specialized micromount box, which protects the specimen from dust, moisture, and mechanical damage. A label with the exact location and confirmed identification is crucial for the specimen's value.