Slavkovite

Chemical formula: Cu₂+₁₃(As₅+O₄)₆(As₅+O₃OH)₄·₂₃H₂O

Slavkovite is a very rare, hydrated copper arsenate with a characteristic blue-green color and acicular crystals.

## Characteristics Slavkovite is a very rare secondary mineral from the arsenate group. It forms characteristic, fine, acicular or bladed crystals, which often form spherical or radial aggregates and crusts. Its typical appearance is delicate, silky or vitreous aggregates of an intense blue-green color, growing on the host rock (most often limonite). ## Physical Properties Slavkovite crystals are very small and brittle. This mineral is characterized by a vitreous or silky luster. It is translucent. Due to the small size of the crystals, precise determination of its physical properties, such as hardness or density, is difficult. ## Colors and Varieties Slavkovite occurs in a uniform, blue-green color. No color or commercial varieties have been distinguished. ## History and Name The mineral's name comes from its discovery location – the historic mining town of Slavkov u Brna (German: Austerlitz) in the Czech Republic. It was first described in 1999 by a team of mineralogists: T. Řídkošil, V. Šrein, J. Sejkora, D. Bělohlav, and J. Černý. ## Uses Slavkovite has no industrial application. Its significance is solely scientific and collectible, being a valuable acquisition for specialized collectors due to its rarity and aesthetic appearance.

Properties

Mohs hardness: 2-3
Luster: Vitreous
Streak: Light green
Density: 3.25
Cleavage: Perfect on {100}
Fracture: Splintery
Transparency: Translucent
Crystal system: Monoclinic

Diagnostic features

## Identification Slavkovite can be identified by its characteristic blue-green color and mode of occurrence – it forms fine, acicular crystals gathered in radial or spherical aggregates with a silky luster. It usually occurs on a limonitic rock matrix. ## Distinguishing from Similar Minerals It can be confused with other secondary copper minerals, such as geminite, lindackerite, cyanotrichite, or brochantite. Distinguishing it from these minerals often requires advanced analytical methods, such as X-ray diffraction (XRD). A key indicator is its co-occurrence with other rare arsenates in a specific geological environment. ## Crystal Forms Crystals are very small, acicular or bladed, elongated along the [010] axis. They usually form radial, stellate, or spherical aggregates, as well as thin crusts and coatings.

Geological environment

## Genesis Slavkovite is a secondary mineral that forms in the oxidation (weathering) zones of polymetallic ore deposits rich in arsenic. It is formed as a result of low-temperature hydrothermal processes occurring most often in voids and fractures of highly weathered rocks, such as limonite. ## Mineral Associations This mineral co-occurs with other rare arsenates and sulfates. It is most often accompanied by: geminite, lindackerite, bukovskýite, arsenopyrite, gypsum, jarosite, and limonite, which constitutes the host rock. ## Localities The most important and type locality for slavkovite is the old dump of the "Schnödův peň" iron ore mine near the town of Slavkov u Brna in the Czech Republic. This is the only confirmed and well-documented occurrence of this mineral in the world.

Rarity

Extremely rare

For collectors

## Quality Criteria The most prized slavkovite specimens are those that possess rich, well-formed, and undamaged aggregates of acicular crystals with an intense blue-green color. The contrast with the rock matrix (most often dark limonite) and the extent of surface coverage are also important. Due to the microscopic size of the crystals, specimens suitable for viewing under magnification are particularly sought after. ## Popular Localities The only source of collectible specimens is the type locality in the Czech Republic (Slavkov u Brna). Material from this location is extremely rare and very difficult to acquire on the market.

Care and storage

## Cleaning Slavkovite specimens are extremely delicate and brittle. They should be cleaned very carefully, using only compressed air to remove dust. Any contact with water, and especially with chemicals, is highly inadvisable and can lead to damage or dissolution of the mineral. ## What to Avoid Contact with water and all liquids must be strictly avoided. The mineral is sensitive to shocks, impacts, and abrasion. It should not be heated or exposed to ultrasound. Due to its arsenic content, avoid inhaling dust and wash hands after contact with the specimen. ## Storage Slavkovite specimens are best stored in closed, stable containers (e.g., "membrane boxes") that protect them from dust, moisture, and mechanical damage. Avoid places with fluctuating humidity and temperature.

Sources

IMA Mineral List (CNMNC)