Ivanyukite-Cu

Chemical formula: Cu²⁺Ti⁴⁺₄(SiO₄)₃O₂(OH)₂·7H₂O

Iwanyukite-Cu is a very rare titanosilicate mineral with an intensely green color, occurring as spherical aggregates.

## Characteristics Iwanyukite-Cu is a hydrated copper titanosilicate, belonging to the iwanyukite group. It forms characteristic spherical or hemispherical aggregates with a radial internal structure, reaching up to 2 mm in diameter. The individual crystals forming the aggregates are lamellar or bladed and measure less than 10 micrometers, making them visible only under high magnification. ## Physical Properties This mineral is characterized by a silky or dull luster. It is translucent. Due to the microscopic size of the crystals and the nature of the aggregates, precise determination of hardness is difficult, but it is estimated to be around 3 on the Mohs scale. The calculated density is 2.83 g/cm³. ## Colors and Varieties Iwanyukite-Cu occurs in a uniform, light green color. No color varieties or commercial varieties are known. ## History and Name The mineral was approved by the IMA in 2011 (IMA2011-015). Its name refers to its kinship with other minerals from the iwanyukite group (iwanyukite-K, -Na, -H) and to the dominant copper (Cu) cation in its composition. The group name honors the Russian geologist and mineralogist Gregory

Properties

Mohs hardness
4
Color
Green
Luster
Silky
Streak
Pale green
Density
2.70
Cleavage
{100}
Fracture
Step-Like
Transparency
Translucent
Crystal system
Isometric

Diagnostic features

## Identification Iwanyukite-Cu can be identified by its unique mode of occurrence as light green, spherical aggregates with a radial internal structure. Its occurrence is limited to a specific geological environment – highly alkaline pegmatites. Due to the microscopic size of the crystals, final identification requires advanced analytical methods, such as X-ray diffraction (XRD) or chemical analysis (EDS/WDS). ## Differentiation from Similar Minerals Due to its color and aggregate form, it can be confused with other secondary copper minerals, such as malachite or chrysocolla. However, malachite usually exhibits concentric bands of various shades of green and effervesces with hydrochloric acid, which is not observed in iwanyukite-Cu. Chrysocolla has a similar appearance but is amorphous or cryptocrystalline and often has a lower luster and lower hardness. ## Crystal Forms This mineral forms spherulitic (spherical) aggregates up to 2 mm in diameter. These aggregates are composed of extremely small, thin, bladed or lamellar crystals, which are arranged radially from the center of the aggregate.

Geological environment

## Genesis Iwanyukite-Cu is a secondary mineral, forming in the late stages of hydrothermal processes in highly alkaline pegmatites. It crystallizes in rock cavities and fissures as a result of alterations of earlier titanium- and silicon-bearing minerals in the presence of copper-rich solutions. ## Mineral Associations This mineral occurs in association with other rare minerals typical of this environment. It is most often accompanied by: vinogradovite, natrosilite, lomonosovite, vuonnemite, as well as the copper sulfide chalcocite, which is the probable source of copper for iwanyukite-Cu. ## Localities The only confirmed locality of iwanyukite-Cu in the world (type locality) is the Khibiny Massif on the Kola Peninsula in Russia. The mineral was found there in the Koashva pegmatite, which is known for the occurrence of many unique and rare minerals.

Rarity

Very rare

For collectors

## Quality Criteria As a mineral with microscopic crystals, iwanyukite-Cu is primarily valued for its mere presence in a collection. The most desirable specimens are those that possess well-formed, spherical aggregates of an intense, light green color, clearly contrasting with the host rock (matrix). The size of the aggregates and their abundance on the specimen significantly increase its value. The aesthetics of the entire matrix and the presence of well-identified associated minerals are also important. ## Popular Localities The only source of iwanyukite-Cu specimens is its type locality – the pegmatite from Koashva Mountain in the Khibiny Massif on the Kola Peninsula in Russia. All specimens available on the collector's market come from this single location, which makes them particularly sought after by collectors specializing in rare minerals, systematic minerals, or minerals from this specific massif.

Care and storage

Yusovich. The use of this mineral is purely scientific and for collecting.

External references

Sources

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