Romanorlovite

Chemical formula: K₁₁Cu₂+₉Cl₂₅(OH)₄·₂H₂O

Romanorlovite is an extremely rare, hygroscopic copper potassium chloride of intense blue color, found in the fumaroles of Tolbachik volcano.

## Characteristics Romanorlovite is a complex hydrated copper potassium chloride. It forms small, tabular or short-prismatic crystals, rarely exceeding 0.4 mm. It occurs as single, well-formed crystals, their radial aggregates, or thin crusts on porous, basaltic volcanic scoria. Its most characteristic feature is an intense, azure-blue color, which can transition into greenish-blue hues. ## Physical Properties This mineral is transparent and characterized by a vitreous luster. It is relatively soft, with a Mohs hardness of approximately 2.5. Due to the microscopic size of the crystals, features such as cleavage have not been observed, and the fracture is uneven. It is a brittle mineral. ## Colors and Varieties The dominant color of romanorlovite is intense blue (azure). Some specimens may exhibit a greenish tint. No color or commercial varieties are distinguished. ## History and Name The mineral was officially recognized by the International Mineralogical Association (IMA) in 2018. Its name honors Roman V. Orlov (born 1974), a Russian mineral collector and photographer specializing in microminerals, who contributed to the discovery of many new species from Tolbachik volcano. The type locality is the Arsenatnaya fumarole on the second cinder cone of the Northern Breakthrough of the Great Fissure Eruption of Tolbachik volcano in Kamchatka, Russia.

Properties

Mohs hardness: 2.5
Luster: Vitreous
Streak: Light blue
Density: 2.86
Cleavage: None
Fracture: Uneven
Transparency: Transparent
Crystal system: Monoclinic

Diagnostic features

## Identification Key diagnostic features include its unique locality, intense blue color, vitreous luster, and occurrence as small, tabular crystals on volcanic scoria. It is a microscopic mineral, so a microscope is essential for its observation. ## Distinguishing from Similar Minerals It can be confused with other blue or green copper chlorides from the same locality, such as avdoninite, eriochalcite, or tolbachite. Visual differentiation is extremely difficult or impossible. Certain identification requires advanced analytical methods, such as X-ray diffraction (XRD) or X-ray microanalysis (EDS). ## Crystal Forms Crystals are most often tabular or short-prismatic. They form radial or chaotic aggregates, as well as thin crusts and coatings on the surface of the host rock.

Geological environment

## Genesis Romanorlovite is a fumarolic mineral. It forms as a result of the sublimation of volcanic gases at high temperatures (above 450°C) under oxidizing conditions. It crystallizes directly from the gas phase on the walls of fumarole channels and on the surface of basaltic scoria. ## Mineral Associations It co-occurs with other rare fumarolic minerals, mainly chlorides and sulfates. The most common associated minerals include avdoninite, eriochalcite, mitscherlichite, as well as halite and sylvine. ## Localities The only known occurrence of romanorlovite in the world is its type locality – the Arsenatnaya fumarole on Tolbachik volcano (Kamchatka, Russia).

Rarity

Extremely rare

For collectors

## Quality Criteria The quality of romanorlovite specimens, being a mineral for specialized micromineral collectors, is assessed based on several criteria. The most important are the sharpness and degree of crystal development, their size (although always small), and the intensity and purity of the color. Rich specimens with numerous, well-separated crystals on a small fragment of host rock are highly valued. An additional advantage is the co-occurrence with other rare, well-identified minerals. ## Popular Localities All collector specimens come from a single location in the world – the fumarole of Tolbachik volcano in Kamchatka.

Care and storage

## Cleaning Romanorlovite is an extremely sensitive mineral and should not be wet cleaned. It is hygroscopic and reacts with water. For dust removal, only compressed air from a safe distance or a very soft, dry brush should be used. ## What to Avoid Contact with water, water vapor, and high humidity, which can cause its decomposition, must be strictly avoided. It should be protected from contact with all chemicals, as well as from sudden temperature changes. Storage in direct sunlight is not recommended. ## Storage Romanorlovite specimens must be stored in sealed, airtight containers (e.g., "perky box" type or membrane boxes), preferably with a desiccant (e.g., silica gel). This provides protection against atmospheric moisture, which is its greatest threat.

Sources

IMA Mineral List (CNMNC)