Vergasovaite
Chemical formula: Cu²⁺₃O(Mo⁶⁺O₄)(S⁶⁺O₄)
Vergasovaite is a rare copper sulfate-molybdate, forming tiny, tabular crystals of an intense green color.
Properties
- Mohs hardness
- 4-5.5
- Color
- Olive-green
- Luster
- Vitreous
- Streak
- Light yellow
- Density
- 0
- Cleavage
- Perfect on {010}
- Fracture
- Irregular/Uneven
- Transparency
- Transparent
- Crystal system
- Orthorhombic
Diagnostic features
## Identification Characteristic features of vergasovaite include its intense green color, vitreous luster, and occurrence as tiny, tabular crystals forming rosette-like aggregates. Crucial for identification is its specific environment of occurrence – volcanic fumaroles. ## Distinguishing from Similar Minerals It can be confused with other green-colored secondary copper minerals, such as brochantite, antlerite, or atacamite. Differentiation requires advanced analytical methods, such as X-ray diffraction (XRD) or chemical analysis (EDS), due to the presence of molybdenum, which is a key diagnostic feature. ## Crystal Forms Crystals are most often thin-tabular, elongated, with a hexagonal or rhombic outline. They usually form small, radial or rosette-like aggregates on the surface of the host rock.
Geological environment
## Genesis Vergasovaite is a mineral of volcanic origin, formed by sublimation from volcanic gases in high-temperature fumaroles (above 600°C). It crystallizes directly from the gas phase on the surfaces of volcanic rocks. ## Mineral Associations It co-occurs with other fumarolic minerals, such as tenorite, hematite, anglesite, chalcanthite, as well as rarer species like piipite, kamchatkite, lammerite, euchlorine, or watsonite. ## Localities The only confirmed and type locality for vergasovaite in the world are the fumaroles associated with the Second Scoria Cone Eruption of the Great Fissure of Tolbachik volcano on the Kamchatka Peninsula in Russia.
Rarity
Very rare
For collectors
## Quality Criteria As a micromineral, vergasovaite is valued for the quality and development of its crystals, rather than their size. The most desirable specimens are those with sharp, well-formed, transparent crystals forming aesthetic, rosette-like aggregates. Contrast with the light host rock and the abundance of associated minerals are also important. ## Popular Localities All collector specimens come from a single location in the world – the Tolbachik volcano in Kamchatka. Material from this locality is highly prized by collectors specializing in rare minerals and microminerals.
Care and storage
## Cleaning Specimens should only be cleaned very carefully, using compressed air to remove dust. Due to the fragility and small size of the crystals, contact with water or brushes is highly inadvisable and can lead to the destruction of the specimen. ## What to Avoid Avoid contact with water, chemicals, acids, and detergents. The mineral is sensitive to shock and abrasion. It should not be heated or exposed to sudden temperature changes. ## Storage Vergasovaite specimens, as microminerals, should be stored in specialized "micromount" boxes that protect them from mechanical damage and dust. Avoid areas with high humidity.