Kobokoboite

Chemical formula: Al₆(PO₄)₄(OH)₆·₁₁H₂O

Kobokoboit is an extremely rare hydrated aluminum phosphate, forming tiny, white aggregates with a pearly luster, known only from one locality in the world.

## Characteristics Kobokoboit is a hydrated aluminum phosphate with a very complex structure. It occurs as small, spherical or hemispherical aggregates, rarely exceeding 1 mm in diameter. These aggregates are composed of extremely fine, lamellar or fibrous crystals, which can only be seen under high magnification. Due to the size of the crystals, individual forms are difficult to observe with the naked eye. The mineral typically has a white color and a characteristic pearly luster on the aggregate surfaces. ## Physical Properties Kobokoboit crystals are extremely small and brittle. Hardness is difficult to measure precisely but is estimated at approximately 2 on the Mohs scale. The luster observed on aggregates is pearly, while individual, microscopic crystals may exhibit a vitreous luster. It is a light mineral, with a density of approximately 2.25 g/cm³. ## Colors and Varieties This mineral is monochromatic – it occurs exclusively in white. No color or commercial varieties have been distinguished. ## History and Name Kobokoboit was discovered and described in 1999 by Paul Piret and Michel Deliens. Its name comes from the discovery locality – the Kobokobo pegmatite in South Kivu Province, Democratic Republic of Congo. This is the only known occurrence of this mineral in the world (type locality). ## Uses Due to its extreme rarity and microscopic size, kobokoboit has no industrial applications. It is solely an object of scientific interest and a valuable acquisition for specialized collectors of rare minerals (so-called "micromounts").

Properties

Mohs hardness: 2
Luster: Pearly
Streak: White
Density: 2.25
Cleavage: Perfect on {010}
Fracture: Uneven
Transparency: Translucent
Crystal system: Triclinic

Diagnostic features

## Identification Amateur identification of kobokoboit is practically impossible. Recognition relies on its unique appearance – small, white, spherical aggregates with a pearly luster, occurring in a specific pegmatitic environment. The location is crucial – this mineral is known exclusively from the Kobokobo pegmatite. Final confirmation requires advanced analytical methods, such as X-ray diffraction (XRD) and chemical analysis (EDS). ## Distinguishing from Similar Minerals Kobokoboit can be confused with other secondary phosphate minerals forming white coatings and aggregates, such as wardite, crandallite, or wavellite. It is distinguished from them by the characteristic, delicate, pearly sheen on the surface of spherical aggregates and its unique structure visible under an electron microscope. Definitive differentiation without specialized equipment is not possible. ## Crystal Forms Kobokoboit forms microscopic, elongated, lamellar crystals that combine into radial, spherical, or hemispherical aggregates. Individual, well-formed crystals are extremely rare and visible only with advanced equipment, such as a scanning electron microscope (SEM).

Geological environment

## Genesis Kobokoboit is a secondary phosphate mineral. It forms in the weathering zones of granite pegmatites rich in lithium and phosphorus. It is created through the alteration and decomposition of primary phosphates, such as lithiophilite, under low temperature and pressure conditions, with the involvement of meteoric waters. ## Mineral Associations This mineral occurs in association with other rare phosphates and secondary minerals. It most commonly co-occurs with quartz, muscovite, crandallite, wardite, strengite, cyrilite, as well as rare minerals such as burangaite and bertossaite. It often grows on other minerals, forming delicate coatings. ## Localities The only confirmed and described occurrence of kobokoboit in the world is the Kobokobo pegmatite, located in the Mwenga region, South Kivu Province in the Democratic Republic of Congo. This is its type locality and, so far, the only known one.

Rarity

Extremely rare

For collectors

## Quality Criteria The quality of kobokoboit specimens is primarily assessed based on the richness and aesthetics of the aggregates on the rock matrix. The most prized samples are those with numerous, well-formed, white spheres that clearly contrast with the darker substrate. The absence of damage to the delicate aggregates and the presence of interesting associated minerals are also important. Due to its microscopic nature, the size of individual aggregates is not a key criterion; the overall composition of the specimen is what matters. ## Popular Localities The only source of kobokoboit specimens is its type locality – the Kobokobo pegmatite in the Democratic Republic of Congo. All samples available on the collector's market originate from this single location.

Care and storage

## Cleaning Kobokoboit specimens are extremely delicate and susceptible to mechanical damage. Cleaning should be limited to an absolute minimum. If necessary, compressed air (from a safe distance) can be used to remove loose dust particles. Any contact with water, brushes, or other tools should be avoided. ## What to Avoid Contact with water and all chemicals, including acids and solvents, must be strictly avoided. The mineral is sensitive to changes in temperature and humidity. It should not be heated or exposed to direct sunlight, which can lead to its dehydration and destruction. ## Storage Kobokoboit specimens, usually in the form of "micromounts," must be stored in stable conditions, in sealed, closed "perky boxes." This protects them from dust, mechanical damage, and humidity fluctuations. Display is only possible under a microscope.

Sources

IMA Mineral List (CNMNC)