Kamotoite-(Y)

Chemical formula: Y₂O₄(U⁶⁺O₂)₄(CO₃)₃·14H₂O

Kamotoite-(Y) is a very rare, bright yellow yttrium uranyl carbonate mineral, known exclusively from one locality in the world.

## Characteristics Kamotoite-(Y) is a hydrated uranyl and yttrium carbonate. It forms very small, acicular or bladed crystals, which typically form radial aggregates, rosettes, or spherulitic clusters. Individual crystals rarely exceed 1 mm in length. Due to its chemical composition, this mineral is highly radioactive. ## Physical properties Kamotoite-(Y) crystals exhibit a bright yellow color and vitreous luster. They are transparent to translucent. Hardness and density have not been precisely measured due to the small size and rarity of the crystals. ## Colors and varieties This mineral occurs in a characteristic, bright, canary-yellow color. No varieties are known. ## History and name Kamotoite-(Y) was described in 1986 by Michel Deliens and Paul Piret. Its name refers to the discovery locality – the Kamoto mine in the Democratic Republic of Congo, and the suffix "-(Y)" indicates the dominance of yttrium (Y) from the rare-earth elements group in its composition. ## Uses Kamotoite-(Y) has no industrial application. It is solely an object of scientific interest and constitutes a valuable and sought-after specimen in advanced collections of rare and radioactive minerals.

Properties

Luster
Vitreous
Streak
Yellow
Density
0
Transparency
Transparent to translucent
Crystal system
Monoclinic

Diagnostic features

## Identification Key diagnostic features include its bright yellow color, characteristic radial or spherulitic aggregates of small, acicular crystals, and very strong radioactivity. The mineral also exhibits intense, green fluorescence under ultraviolet light (both short-wave and long-wave). ## Distinguishing from similar minerals Kamotoite-(Y) can be confused with other secondary yellow uranium minerals, such as studtite, meta-studtite, or schoepite. Distinguishing it from these minerals often requires advanced analytical methods, such as X-ray diffraction (XRD) or chemical analysis (EDS), due to the similarity in form and color. ## Crystal forms Crystals are very small, elongated, acicular, or bladed. They most often occur as radial aggregates, rosettes, and spherical clusters (spherulites) up to 2 mm in diameter.

Geological environment

## Genesis Kamotoite-(Y) is a secondary mineral formed in the oxidation zones of uranium deposits. It forms as a result of weathering and alteration of primary uranium minerals, such as uraninite, in an environment rich in carbonates and rare-earth elements, especially yttrium. ## Mineral associations This mineral co-occurs with other secondary uranium minerals. At the type locality, it was found in association with uranophane, schoepite, becquerelite, curite, and also astrocianite-(Ce). ## Localities The only confirmed locality for kamotoite-(Y) in the world is its type locality: the Kamoto East open pit, part of the Kamoto mine in Lualaba Province, Democratic Republic of Congo.

Rarity

Extremely rare

For collectors

## Quality criteria The most highly valued specimens are those with well-formed, distinct spherulitic aggregates of intense yellow color, contrasting with the dark matrix rock. The size of the aggregates and the absence of mechanical damage are also important. The presence of rare associated minerals, such as astrocianite-(Ce), can further increase the value of the specimen. ## Popular localities The only source of specimens of this mineral is the Kamoto mine in the Democratic Republic of Congo. Material from this locality is extremely rare on the collector's market.

Care and storage

## Cleaning Specimens should not be wet cleaned. Only gentle dust removal with a soft brush or compressed air from a safe distance is permissible. ## What to avoid Contact with water and chemicals, which can damage delicate crystals, must be strictly avoided. As a highly radioactive mineral, it requires specialized safety precautions. Direct skin contact, inhalation of dust, and storage in areas of permanent human presence should be avoided. ## Storage Kamotoite-(Y) specimens must be stored in specialized, sealed, and appropriately labeled containers, preferably with radiation shielding (e.g., lead). They should be kept away from other minerals that could be damaged by radiation.

External references

Sources

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