Clinobisvanite

Chemical formula: Bi₃+V₅+O₄

Clinobisvanite is a bismuth and vanadium mineral, distinguished by its intense, lemon-yellow to orange-yellow color.

## Characteristics Clinobisvanite is a bismuth vanadate and represents the monoclinic polymorph of pucherite. It most commonly occurs as earthy or powdery coatings and aggregates, less frequently forming small, well-formed crystals. Its most characteristic feature is its bright, intense color, which makes it easily noticeable despite its small size. ## Physical Properties This mineral is characterized by a hardness ranging from 4 to 5 on the Mohs scale, making it relatively soft. It is extremely dense (approx. 6.95 g/cm³), which is noticeable even in small specimens. The luster is described as adamantine to resinous or greasy. Crystals can be transparent to translucent, while massive aggregates are opaque. ## Colors and Varieties Clinobisvanite exhibits colors from bright yellow, through lemon-yellow, greenish-yellow, to orange-yellow. No color or commercial varieties are distinguished. It is the natural analogue of synthetic bismuth vanadate, used as a stable, non-toxic pigment. ## History and Name The mineral's name refers to its chemical composition (bismuth and vanadium) and its monoclinic (from Greek *klino* - "to incline") crystallographic system. It was formally described as a new mineral in 1974 by P.J. Bridge and M.W. Pryce based on material from Yinnietharra Station in Western Australia. ## Applications Due to its rarity and small occurrences, clinobisvanite has no industrial applications. However, it is a valued and sought-after collector's mineral.

Properties

Mohs hardness: 4-5
Luster: Adamantine to resinous
Streak: Light yellow
Density: 6.95
Cleavage: Good on {010}
Fracture: Conchoidal to uneven
Transparency: Transparent to translucent
Crystal system: Monoclinic

Diagnostic features

## Identification The key diagnostic features of clinobisvanite are its intense yellow color, very high density, and occurrence in the oxidation zones of ore deposits. The streak is light yellow. The luster is most often adamantine or resinous. ## Distinguishing from Similar Minerals Clinobisvanite can be confused with its polymorph, pucherite, from which it is practically impossible to distinguish without X-ray diffraction (XRD) analysis. Pucherite more often takes reddish-brown hues. It may resemble yellow wulfenite, which is, however, softer (2.5-3) and crystallizes in the tetragonal system, forming characteristic tabular crystals. It is distinguished from native sulfur by its significantly greater hardness and density. ## Crystal Forms Well-formed crystals are rare and usually very small, with a tabular or prismatic habit. It is most commonly found as earthy, powdery, or reniform aggregates and coatings on other minerals.

Geological environment

## Genesis Clinobisvanite is a secondary mineral, formed in the oxidation zones of hydrothermal ore deposits rich in bismuth and vanadium. It forms as a result of weathering and alteration of primary bismuth minerals, such as bismuthinite. ## Mineral Associations It often co-occurs with other secondary minerals, such as bismutite, pucherite, mottramite, mimetite, vanadinite, as well as iron oxides (goethite, hematite) and quartz. ## Localities The most important localities worldwide include the type locality Yinnietharra Station in Western Australia, where it occurs as coatings. Small but well-formed crystals are known from the Berezovskoye gold deposit in the Urals, Russia. Occurrences have also been reported in Great Britain (Muttram St Andrew), Namibia, Germany, and in Arizona and California in the USA.

Rarity

Rare

For collectors

## Quality Criteria The most highly valued specimens are those with well-formed, sharp crystals of intense, pure color and strong luster. Since large crystals are extremely rare, even rich aggregates of microcrystals on a rock matrix are attractive. Aesthetic associations with other colorful secondary minerals are also highly rated. ## Popular Localities Specimens from Yinnietharra in Australia are considered classic. The best microcrystals, sought after by collectors specializing in rare minerals, come from the Berezovskoye deposit in Russia.

Care and storage

## Cleaning Clinobisvanite specimens should be cleaned very carefully, using only distilled water and a soft brush. Ultrasonic cleaners should be avoided, as they can damage delicate crystals or aggregates. ## What to Avoid The mineral is relatively soft and susceptible to scratching. It should be protected from contact with harder minerals. It is sensitive to strong acids. It does not require special protection from light, but it is recommended to avoid extreme temperature changes. ## Storage It is recommended to store specimens in separate, padded boxes or display cases to prevent abrasion and mechanical damage. Due to its high density, it is quite brittle and sensitive to drops.

Sources

IMA Mineral List (CNMNC)