Shlykovite

Chemical formula: KCa[Si₄O₉(OH)]·₃H₂O

Shlykovite is a very rare, colorless silicate mineral, forming unique, spherical aggregates with a pearly luster.

## Characteristics Shlykovite is a hydrated potassium and calcium silicate, belonging to a group of very rare minerals. It occurs as small, spherical or spherulitic aggregates, typically not exceeding 1 mm in diameter. These aggregates are composed of extremely fine, thin, lamellar crystals. Due to its appearance, it is sometimes compared to a sea urchin or a dandelion. ## Physical Properties Shlykovite crystals are flexible and have a hardness of approximately 2 on the Mohs scale. The mineral is characterized by a pearly luster on the surface of the aggregates and a vitreous luster on individual lamellae. It is transparent to translucent. Its calculated density is 2.21 g/cm³. ## Colors and Varieties Shlykovite is colorless and does not form colored varieties. ## History and Name The mineral was discovered in material from the Khibiny Massif on the Kola Peninsula in Russia. It was approved by the International Mineralogical Association (IMA) in 2009 (IMA2009-065). The name honors Maria Georgievna Shlykova (1920-1985), a Russian crystallographer and mineralogist from St. Petersburg University, who made significant contributions to the study of silicates.

Properties

Mohs hardness: 2.5-3
Color: Greyish white to slightly beige
Luster: Pearly
Streak: White
Density: 2.244
Cleavage: Parallel to (001).
Fracture: Uneven
Transparency: Transparent
Crystal system: Monoclinic

Diagnostic features

## Identification A characteristic feature of shlykovite is its unique, spherical aggregates with a radial structure, resembling dandelions or sea urchins. The pearly luster of these aggregates and their occurrence in a specific geological environment are crucial for identification. ## Distinguishing from Similar Minerals Shlykovite can be confused with other silicates that form radial aggregates, such as some zeolites (e.g., mesolite, natrolite) or reyerite. However, it is distinguished by its specific spherical morphology, lower hardness, and unique occurrence environment in agpaitic pegmatites. ## Crystal Forms It forms spherulitic aggregates up to 1 mm in diameter, composed of very thin, lamellar or platy crystals arranged radially. Individual crystals are too small to be observed with the naked eye.

Geological environment

## Genesis Shlykovite forms in the late stages of hydrothermal processes in highly alkaline (agpaitic) nepheline syenite pegmatites. It crystallizes in rock cavities and fissures. ## Mineral Associations This mineral co-occurs with other rare minerals typical of the Khibiny Massif pegmatites, such as vinogradovite, lorenzenite, natrolite, aegirine, microcline, nepheline, sodalite, and eudialyte. ## Localities The only confirmed locality of shlykovite in the world (type locality) is Mount Koashva in the Khibiny Massif, on the Kola Peninsula in Murmansk Oblast, Russia.

Rarity

Very rare

For collectors

## Quality Criteria The most prized specimens are those with well-formed, undamaged spherulitic aggregates that stand out clearly from the host rock (matrix). Color contrast, for example with dark aegirine, enhances visual appeal. Due to their microscopic size, the quality of the specimen under magnification is key. ## Popular Localities The only source of specimens of this mineral is the Khibiny Massif in Russia, which makes every specimen from there unique.

Care and storage

## Cleaning Due to the extreme delicacy and small size of the aggregates, mechanical cleaning is not recommended. If necessary, compressed air can be used from a safe distance to remove loose dust. Contact with water should be avoided, as it can damage the mineral's structure. ## What to Avoid Contact with chemicals, acids, and detergents must be strictly avoided. The mineral is very soft and brittle, sensitive to any shocks, scratches, and pressure. Heating can lead to water loss and structural damage. ## Storage Shlykovite specimens require storage in specialized, sealed "micromount" boxes that protect them from dust, humidity, and mechanical damage. Exposure to direct sunlight and temperature changes should be avoided.

External references

https://www.mindat.org/min-39308.html