Kurumsakite

Chemical formula: Zn₂+₈Al₈V₅+₂Si₅O₃₅·₂₇H₂O

Kurumsakite is a very rare hydrated zinc, aluminum, and vanadium silicate, forming microscopic, yellow, hexagonal crystals.

## Characteristics Kurumsakite is a hydrated zinc, aluminum, and vanadium silicate, belonging to the phyllosilicate group. It occurs as extremely small, hexagonal, platy crystals, rarely exceeding 0.1 mm in size. These crystals often form rosette-like or spherulitic aggregates. Due to its microscopic size, it is a mineral primarily accessible to specialized collectors and scientific institutions. ## Physical Properties Kurumsakite crystals exhibit a vitreous luster. Hardness and density have not been precisely measured due to the small size of the samples, however, the density calculated based on the formula and unit cell parameters is 2.51 g/cm³. It is a very brittle mineral. ## Colors and Varieties Kurumsakite has a characteristic, pale yellow to canary yellow color. No color varieties or commercial varieties are known. ## History and Name The mineral was discovered in the Kara-Chagyr vanadium deposit in the Alay Mountains, Kyrgyzstan, as well as in the Kurumsak deposit in Kazakhstan. It was described and approved as a new mineral species by the International Mineralogical Association (IMA) in 1994. Its name comes from its discovery locality – the Kurumsak deposit. ## Applications Kurumsakite has no industrial applications. Its significance is purely scientific and for collectors.

Properties

Mohs hardness: 2
Luster: Vitreous
Streak: Light yellow
Density: 2.51
Cleavage: Perfect on {0001}
Fracture: Uneven
Transparency: Transparent to translucent
Crystal system: Hexagonal

Diagnostic features

## Identification Identification of kurumsakite is impossible without advanced laboratory equipment. Identification requires chemical analysis (EDS) and X-ray structural analysis (XRD) to confirm its composition and crystal structure. Visually, under high magnification, characteristic yellow, hexagonal, platy crystals or rosettes can be observed. ## Distinguishing from Similar Minerals It can be confused with other secondary, yellow vanadium minerals, such as carnotite or tyuyamunite, which often co-occur in the same environments. Differentiation is only possible based on chemical analysis, as kurumsakite contains zinc, aluminum, and silicon, unlike uranyl vanadates like carnotite. ## Crystal Forms It forms thin, platy crystals with a hexagonal outline. These crystals often combine into small, radial or rosette-like aggregates, as well as spherulites.

Geological environment

## Genesis Kurumsakite is a secondary mineral, forming in the oxidation zones of polymetallic deposits containing vanadium. It forms in highly weathered, black siliceous shales, which are rich in organic matter, vanadium, uranium, zinc, and molybdenum. It originates from the weathering of primary vanadium and base metal minerals under conditions of low temperatures and pressures. ## Mineral Associations It most commonly co-occurs with gypsum, as well as with other rare vanadium minerals such as satpaevite, alvanite, carnotite, tyuyamunite, hewettite, and rossite. Associated minerals also include quartz and chalcedony. ## Localities The main and only confirmed occurrences of kurumsakite are its type localities: the Kurumsak vanadium deposit in the Karaganda Region, Kazakhstan, and the Kara-Chagyr deposit in the Alay Mountains, Kyrgyzstan.

Rarity

Very rare

For collectors

## Quality Criteria The quality of kurumsakite specimens is assessed primarily based on the richness and development of microscopic crystals on the rock matrix. Specimens with numerous, well-formed, rosette-like aggregates of intense yellow color are most valued. Due to the microscopic nature of the mineral, the size of individual crystals is not a key criterion; the overall aesthetics and coverage of the matrix are important. ## Popular Localities The best and practically only available specimens come from two deposits in Central Asia: Kurumsak in Kazakhstan and Kara-Chagyr in Kyrgyzstan. Specimens from these localities are the standard for this mineral.

Care and storage

## Cleaning Kurumsakite specimens are extremely delicate and small, therefore they should not be cleaned mechanically or chemically. Any attempts at cleaning risk irreversible damage to the microscopic crystals. It is safest to leave the specimen in its untouched state. ## What to Avoid Avoid contact with water, chemicals, ultrasound, and any vibrations or impacts. Changes in temperature and humidity can also be harmful. Specimens should not be exposed to direct sunlight. ## Storage Specimens should only be stored in specialized, sealed "micromount" boxes that protect against dust, moisture, and mechanical damage. The box should be kept in stable conditions, away from heat sources and vibrations.

Sources

IMA Mineral List (CNMNC)