Šlikite

Chemical formula: Zn<sup>2+</sup><sub>2</sub>Mg(CO<sub>3</sub>)<sub>2</sub>(OH)<sub>2</sub>·4H<sub>2</sub>O

Šlikite is an extremely rare, hydrated basic zinc and magnesium carbonate, forming delicate, silky aggregates of acicular crystals.

## Characteristics Šlikite is a carbonate mineral characterized by its occurrence as very small, acicular crystals. These form radial or tangled aggregates, often in the shape of spherical or hemispherical 'hedgehogs', reaching up to several millimeters in diameter. Due to its microcrystalline structure, individual crystals are usually indistinguishable to the naked eye. The aggregates have a characteristic silky luster. ## Physical Properties The mineral's luster is silky, and the crystals themselves are translucent. Hardness has not been measured due to the small size and fragility of the crystals, but it can be assumed to be very low. The density calculated from the chemical formula and unit cell parameters is 2.61 g/cm³. ## Colors and Varieties This mineral is colorless or white. No color varieties or commercial varieties have been distinguished. ## History and Name Šlikite was recognized as a new mineral by the International Mineralogical Association (IMA) in 2020. Its scientific description was published in 2021. The name comes from the Czech-German aristocratic family Šlik (German: Schlick), who managed the silver mines in the Jáchymov region in the 16th century, where this mineral was discovered. ## Uses As an extremely rare mineral occurring in microscopic specimens, šlikite has no industrial application. It is solely an object of scientific and collecting interest, being a valuable acquisition for specialized collections of rare minerals and systematic collections.

Properties

Luster
Silky
Streak
White
Density
2.61
Cleavage
Perfect on {010}
Transparency
Translucent
Crystal system
Monoclinic

Diagnostic features

## Identification A characteristic feature of šlikite is its unique form of occurrence: white, silky, spherical or radial aggregates composed of very fine, acicular crystals. A key diagnostic element is its origin from the type locality in Jáchymov, where it formed under post-magmatic conditions. ## Differentiation from Similar Minerals Šlikite can be confused with other white, fibrous secondary minerals, such as hydrozincite or aragonite. It can be difficult to distinguish visually from hydrozincite (Zn₅(CO₃)₂(OH)₆), but hydrozincite often exhibits strong, blue fluorescence under UV light, which has not been observed in šlikite. Aragonite (CaCO₃) forms similar aggregates but is much harder and denser. Certain differentiation requires advanced analytical methods, such as Raman spectroscopy or X-ray microanalysis (EDS). ## Crystal Forms The crystals are acicular (needle-like) and elongated along the crystallographic c-axis. They occur exclusively as radial, spherical, or hemispherical aggregates, as well as tangled, fibrous masses.

Geological environment

## Genesis Šlikite is a secondary mineral that formed under low-temperature post-magmatic conditions. It crystallizes from zinc- and magnesium-rich solutions in adits and on dumps of old mines. Its genesis is associated with the weathering of primary zinc ores in the presence of magnesium-rich rocks (e.g., dolomites). ## Mineral Associations This mineral occurs in association with other secondary minerals. At the type locality, it was found in direct proximity to aragonite and calcite. ## Localities The only confirmed occurrence of šlikite in the world is its type locality – the Rovnost I mine (Werner adit) in Jáchymov, Karlovy Vary Region, Czech Republic.

Rarity

Extremely rare

For collectors

## Quality Criteria The collector's value of šlikite specimens depends on several factors. Samples with well-formed, spherical aggregates with a distinct silky luster are most highly prized. The size and richness of these aggregates on the rock matrix are also important. Specimens where šlikite contrasts with the substrate or co-occurs with other minerals are considered more aesthetically attractive. ## Popular Localities All specimens available on the collector's market come from a single location in the world – the Rovnost I mine in Jáchymov, Czech Republic. It is an extremely difficult mineral to acquire, sought after by collectors specializing in rare mineral species or minerals from specific localities (so-called "locality collecting").

Care and storage

## Cleaning Šlikite specimens are extremely delicate and fragile. For dust removal, it is best to use canned compressed air, applied from a safe distance. Any contact with water or other chemicals is highly inadvisable. Mechanical cleaning, even with a soft brush, risks irreversible damage to the acicular crystals. ## What to Avoid Avoid contact with water and all acids, in which the mineral rapidly dissolves. As a hydrated mineral, it is sensitive to elevated temperatures, which can lead to its dehydration and structural damage. It should be protected from shocks, impacts, and abrasion. ## Storage It is recommended to store specimens only in closed, stable containers, preferably in specialized "micromount" boxes, which protect against dust and mechanical damage. Stable environmental conditions should be ensured, without sudden changes in temperature and humidity.

Sources

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