Itelmenite

Chemical formula: Na₂Cu²⁺Mg₂(S⁶⁺O₄)₄

Itelmenite is a rare sodium, copper, and magnesium sulfate, forming characteristic, tabular crystals of an intense blue color.

## Characteristics Itelmenite is a sulfate mineral distinguished by its vivid blue color. It forms very small, tabular or bladed crystals, typically not exceeding 0.2 mm in length. These crystals often occur as radial or chaotic aggregates, as well as single flakes on the surface of other minerals. Due to its small size, it is a mineral primarily observed under a microscope. ## Physical Properties Itelmenite crystals exhibit a vitreous luster. They are transparent and have a pale blue streak. This mineral is brittle, and its hardness and density have not been precisely determined due to the small size of the samples. ## Colors and Varieties Itelmenite occurs in a uniform, intensely blue color. No color varieties or commercial varieties are known. ## History and Name The mineral's name honors the Itelmen people, indigenous inhabitants of the Kamchatka Peninsula, where the mineral was discovered. It was approved by the International Mineralogical Association (IMA) in 2015. The type locality is the fumaroles of Tolbachik volcano in Kamchatka, Russia. ## Uses Itelmenite has no industrial applications. Its significance is purely scientific and as a collector's item, being a rare and interesting micromineral.

Properties

Color: Light grey-blue
Luster: Vitreous
Streak: White
Density: 3.10
Cleavage: Perfect on {0001}
Fracture: Irregular/Uneven
Transparency: Transparent
Crystal system: Orthorhombic

Diagnostic features

## Identification Itelmenite can be identified by its intense blue color, tabular crystal habit, and occurrence as small aggregates. Its origin is key – it occurs in products of volcanic fumarole activity. ## Distinguishing from Similar Minerals It can be confused with other blue volcanic sulfates, such as chalcanthite or cyanotrichite. Differentiation requires advanced analytical methods, such as Raman spectroscopy or chemical analysis (EDS), due to the presence of sodium, copper, and magnesium in its composition. Visually, it is difficult to identify unequivocally. ## Crystal Forms It forms thin, tabular or bladed crystals, often flattened. These crystals combine into radial or irregular aggregates, and also occur as single flakes.

Geological environment

## Genesis Itelmenite is a mineral of volcanic origin. It forms through sublimation from volcanic gases in high-temperature fumaroles (vents from which hot gases emerge). It crystallizes directly from the gas phase on the surface of volcanic rocks. ## Mineral Associations This mineral co-occurs with other sulfates and fumarolic minerals, such as langbeinite, aphthitalite, hematite, tenorite, chalcanthite, eriocalcite, and wulffite. ## Localities The only confirmed locality for itelmenite worldwide is its type locality – the Arsenievskaya and Main Fracture of the North Cone fumaroles of Tolbachik volcano on the Kamchatka Peninsula, Russia.

Rarity

Very rare

For collectors

## Quality Criteria As a micromineral, itelmenite is valued for the quality and formation of crystals visible under magnification. The most desirable specimens are those with clearly formed, undamaged crystals of intense blue color, forming aesthetic aggregates on a contrasting matrix. The size of the crystals, even if sub-millimeter, also increases the specimen's value. ## Popular Localities The only source of itelmenite specimens is the Tolbachik volcanic complex in Kamchatka. Specimens from this locality are the only ones available on the collector's market and hold the status of material from the type locality.

Care and storage

## Cleaning Itelmenite specimens are extremely delicate and small. They should not be cleaned mechanically or chemically. Any attempts at cleaning may destroy the fragile crystal structure. It is best to leave them in their untouched state. ## What to Avoid Avoid contact with water and chemicals, as it may be soluble as a sulfate. Protect it from vibrations, shocks, and high temperatures. It should also not be exposed to ultrasound. ## Storage It is recommended to store specimens only in specialized micromount boxes to protect them from mechanical damage and dust. Display should be away from sources of vibration and direct sunlight.