Chervetite

Chemical formula: Pb²⁺₂V⁵⁺₂O₇

Reddish-brown or yellowish lead pyrovanadate, forming small, tabular crystals with an adamantine luster.

## Characteristics Chervetite is a rare mineral from the vanadate group, chemically classified as lead pyrovanadate. It occurs as very small, tabular or bladed crystals, rarely exceeding 1 mm in length. The crystals are often flattened and can form small, radiating aggregates or rosettes. Due to its size, it is a mineral valued primarily by micromounters. ## Physical Properties Chervetite crystals are characterized by a high, almost adamantine luster, which makes even small specimens clearly visible under magnification. It is a relatively soft and very brittle mineral. Its density is high, which is typical for lead-bearing minerals. ## Colors and Varieties The most common color is reddish-brown to orange-red. Yellow, honey-yellow, and even greenish-yellow specimens are also observed. The mineral does not form named varieties. ## History and Name The mineral was first described in 1963 by Fabien Cesbron and Jean-Pierre Brianson. The name honors Jean Chervet (1897-1962), a French mineralogist and professor at the University of Nancy, in recognition of his contributions to the study of uranium minerals. ## Uses Chervetite has no industrial applications. Its significance is purely scientific and collectible.

Properties

Mohs hardness
2-2.5
Color
Gray to brown
Luster
Adamantine
Streak
White
Density
6.30
Cleavage
{100} and {010}
Fracture
Uneven
Transparency
Transparent
Crystal system
Monoclinic

Diagnostic features

## Identification Chervetite is recognized by its characteristic appearance: small, tabular or bladed crystals with an intense, reddish-brown or yellow color and a very strong, adamantine luster. It occurs in a specific geological environment – the oxidation zones of uranium-vanadium deposits. ## Distinguishing from Similar Minerals It can be confused with other secondary vanadium minerals, such as carnotite or tyuyamunite, which often co-occur. Chervetite differs from them in crystal habit (thin tablets) and significantly stronger luster. Carnotite and tyuyamunite typically form earthy or powdery coatings. Final identification requires advanced analytical methods (e.g., XRD, EDS). ## Crystal Forms It forms thin, tabular crystals, often elongated in one direction, with a bladed habit. Crystals can be grouped into small, radiating or fan-shaped aggregates.

Geological environment

## Genesis Chervetite is a secondary mineral formed in the oxidation zones of hydrothermal polymetallic deposits, especially those rich in uranium and vanadium. It forms as a result of the weathering of primary lead-bearing minerals (e.g., galena) and vanadium in the presence of oxygen-rich solutions. ## Mineral Associations It most often co-occurs with other secondary vanadium and uranium minerals. Typical associated minerals include francevillite, curite, carnotite, tyuyamunite, vanuralite, as well as barite, quartz, and manganese oxides. ## Localities The most important and classic locality, from which the best specimens originate, is the Mounana mine in Gabon. This mineral has also been found in the Rabejac uranium mine in France (Hérault department) and in several locations in the United States, including mines in San Juan County, Utah.

Rarity

Rare

For collectors

## Quality Criteria The most prized specimens are those with well-formed, sharp crystals of intense red color and strong luster. It is important that the crystals are grouped into aesthetic aggregates (e.g., rosettes) on a contrasting substrate (matrix). Due to the small size of the crystals, their quality and form visible under a microscope are crucial. ## Popular Localities Specimens from the type locality – the Mounana mine in Gabon – are by far the most sought after by collectors. They are considered the global standard for this mineral.

Care and storage

## Cleaning Chervetite specimens are extremely delicate and brittle. Mechanical cleaning is highly inadvisable. If absolutely necessary, compressed air (from a safe distance) can be used to remove dust. Avoid contact with water and any chemicals. ## What to Avoid The mineral is sensitive to acids and other chemical reagents. Avoid ultrasound, vibrations, and sudden temperature changes. As a lead-bearing mineral, caution should be exercised, dust inhalation should be avoided, and hands should be washed after handling specimens. ## Storage It is recommended to store specimens exclusively in specialized "micromount" boxes, which protect them from mechanical damage and dust. They should be kept away from sources of vibration and in stable humidity conditions.

External references

Sources

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