Sanguite

Chemical formula: KCu²⁺Cl₃

Sanguite is a rare potassium copper chloride, forming intensely red, acicular crystals in volcanic environments.

## Characteristics Sanguite is a rare mineral from the halide group, specifically a potassium copper chloride. It is distinguished by its intense, blood-red color, from which its name is derived. It typically occurs as small, prismatic or acicular crystals, which can form radial aggregates or crusts on volcanic rocks. Individual crystals are usually very small, rarely exceeding 1 mm in length. ## Physical Properties Sanguite crystals exhibit a vitreous luster. They are transparent to translucent. Due to their small size and rarity, many of their physical properties, such as hardness or density, have not been fully determined. ## Colors and Varieties This mineral is monochromatic – it occurs exclusively in shades from red to reddish-orange. No color varieties or commercial varieties are distinguished. ## History and Name The name sanguite comes from the Latin word *sanguis*, meaning "blood," which is a direct reference to its characteristic, blood-red color. The mineral was first described in 2013 by Igor V. Pekov and his research team. The type locality (place of discovery) was identified as the Yadovitaya fumarole on Tolbachik volcano in Kamchatka, Russia. ## Applications Sanguite has no industrial applications. Its significance is purely scientific and collectible, being a coveted object for collectors specializing in volcanic minerals and micromounts.

Properties

Mohs hardness: 3
Color: Bright red
Luster: Vitreous
Streak: Reddish orange
Density: 2.86
Cleavage: Perfect on (010); another distinct cleavage observed under the microscope is probably on (102), based on angles measured on cleaved pieces and by analogy with the synthetic crystals.
Fracture: Step-Like
Transparency: Transparent
Crystal system: Monoclinic

Diagnostic features

## Identification Key diagnostic features of sanguite include its blood-red color, acicular or prismatic crystal habit, and specific occurrence environment – active volcanic fumaroles. It reacts to moisture, which is a characteristic but also destructive feature. ## Distinguishing from Similar Minerals Sanguite can be confused with other red minerals from the same locality, such as erythrosiderite and kremersite. Differentiation requires advanced analytical methods, such as X-ray diffraction (XRD), due to visual similarity and co-occurrence. It differs from cinnabar by its significantly lower hardness and water solubility. ## Crystal Forms Sanguite forms elongated, prismatic crystals with a nearly square cross-section. They often occur in acicular form, creating radial or chaotic aggregates and crusts on the surface of lava or volcanic tuff.

Geological environment

## Genesis Sanguite is a mineral of volcanic origin, formed by sublimation from volcanic gases. It crystallizes in high-temperature, active fumaroles (volcanic exhalations), where hot gases rich in chlorine and metals react with rocks. It is a typical product of environments with high geothermal activity. ## Mineral Associations This mineral co-occurs with other rare halides and sulfates formed under similar conditions. It is most commonly associated with sylvite, halite, tenorite, hematite, erythrosiderite, kremersite, melanothallite, and newly described minerals from the Tolbachik group. ## Localities The only confirmed and thoroughly described occurrence of sanguite in the world is its type locality – the Yadovitaya fumarole and a second main fumarole, both located within the Great Fissure Eruption of Tolbachik (1975-1976) on Tolbachik volcano, Kamchatka, Russia.

Rarity

Very rare

For collectors

## Quality Criteria The collector's appeal of sanguite primarily depends on the intensity and purity of its red color and the crystal habit. Most valued are specimens with clearly visible, well-formed needles or prisms, creating rich, aesthetic aggregates on a contrasting substrate (matrix). Due to the microscopic size of the crystals, the quality of the specimen is assessed under magnification. ## Popular Localities All sanguite specimens available on the collector's market come from a single location worldwide: Tolbachik volcano in Kamchatka, Russia. It is an extremely difficult mineral to obtain due to the dangerous and inaccessible environment of its formation.

Care and storage

## Cleaning Sanguite specimens are extremely delicate and sensitive. Any mechanical cleaning and contact with liquids should be avoided. If cleaning is absolutely necessary, compressed air (from a safe distance) can be carefully used to remove loose dust particles. ## What to Avoid Sanguite is hygroscopic, meaning it absorbs moisture from the air. Contact with water or storage in a humid environment leads to its dissolution and destruction. All chemicals, ultrasonics, and sudden temperature changes must be strictly avoided. ## Storage Specimens should be stored in sealed, dry containers, preferably with a desiccant (e.g., silica gel). The safest form of display is specialized "micromount" boxes, which protect delicate crystals from mechanical damage and moisture.