Curetonite

Chemical formula: Ba(Al,Ti⁴⁺)(PO₄)(OH,O)F

Curetonite is a rare phosphate mineral of the laueite group, distinguished by its bright, yellowish-green color and occurrence as small, platy crystals.

## Characteristics Curetonite is a hydrated phosphate of barium, aluminum, and titanium, belonging to the laueite group. It forms very small, platy crystals that rarely exceed 1 mm in length. They typically occur as radial or rosette-like aggregates and clusters, as well as thin coatings and crusts on rock surfaces. Its most characteristic feature is its intense, bright green or yellowish-green color. ## Physical Properties This mineral has a hardness of 3.5 on the Mohs scale, making it relatively soft. It has a density of 4.42 g/cm³, which is a high value for a non-metallic mineral. The luster of curetonite is described as vitreous, and its crystals are translucent. ## Colors and Varieties Curetonite occurs in a uniform, characteristic, bright shade of green, often with a yellowish tone. No named color varieties or commercial types are distinguished. ## History and Name The mineral was discovered and described in 1978. Its name honors Forrest E. Cureton (1932-2010), an American mineral collector from Nevada, who first found this mineral and brought it to the attention of researchers. The type locality (locus typicus) is the Redhouse Barite Mine in Humboldt County, Nevada, USA. ## Uses Curetonite has no industrial application. Its significance is purely scientific and as a collector's item, as a rare and interesting micromineral.

Properties

Mohs hardness
3.5
Luster
Vitreous
Streak
White
Density
4.42
Cleavage
Good on {011}
Fracture
Uneven
Transparency
Translucent
Crystal system
Monoclinic

Diagnostic features

## Identification Curetonite can be identified by its characteristic bright green color, small, platy crystals forming rosette aggregates, and its occurrence. It is a secondary mineral found in the oxidation zones of barite deposits. Due to the small size of the crystals, magnification is often necessary for its identification. ## Distinguishing from Similar Minerals It can be confused with other green secondary phosphate minerals, such as torbernite or autunite, but curetonite is not radioactive. It differs from wavellite in crystal habit – curetonite forms plates, while wavellite forms acicular crystals in spherical aggregates. Final distinction from other rare phosphates requires advanced chemical (EDS) or X-ray (XRD) analyses. ## Crystal Forms Curetonite crystals are very small, thin, and platy, with a bladed habit. They most often form radial aggregates, rosettes, or fan-shaped clusters. They also occur as thin coatings on the surface of other minerals.

Geological environment

## Genesis Curetonite is a secondary mineral, formed in the oxidation zones of ore deposits, in this case, a barite deposit. It forms as a result of low-temperature hydrothermal processes that lead to the alteration of earlier minerals. ## Mineral Associations This mineral co-occurs with other rare phosphates and sulfates. At the type locality, it was found in association with barite, quartz, strengite, conichalcite, gorceixite, goethite, wavellite, and minerals from the corkite-hinsdalite group. ## Localities Curetonite is an extremely rare mineral. Besides the type locality – the Redhouse Barite Mine in Humboldt County, Nevada (USA) – its occurrence has been confirmed in only a few other places worldwide, including the Silver Coin Mine in Valmy County, also in Nevada.

Rarity

Very rare

For collectors

## Quality Criteria The quality of a curetonite specimen depends primarily on the richness and aesthetics of the crystal aggregates. Most valued are specimens with well-formed, distinct rosettes or radial clusters of intense, bright green color. Contrast with the rock matrix and the presence of rare associated minerals are also important. Due to the microscopic size of the crystals, specimens are evaluated under magnification. ## Popular Localities The only source of collector specimens is its type locality – the Redhouse Barite Mine in Nevada, USA. All specimens available on the market come from this single location.

Care and storage

## Cleaning Curetonite specimens should be cleaned with the utmost care, preferably using compressed air to remove dust. Due to its softness and small crystal size, mechanical contact is not recommended. If wet cleaning is necessary, use only distilled water and avoid rubbing. ## What to Avoid Avoid contact with all chemicals, especially acids, which can damage the mineral. Curetonite is brittle and soft, so it must be protected from impacts, scratching, and vibrations. It should not be heated or exposed to prolonged strong light. ## Storage The safest way to store curetonite is to place it in a sealed "micromount" box, which protects delicate crystals from dust and mechanical damage. The specimen should be stored under stable room conditions, away from moisture and heat sources.

External references

Sources

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