Krasnoshteinite
Chemical formula: Al<sub>8</sub>[B<sub>2</sub>O<sub>4</sub>(OH)<sub>2</sub>](OH)<sub>16</sub>Cl<sub>4</sub>·7H<sub>2</sub>O
An extremely rare, hydrated aluminum borate, occurring as white, brittle aggregates with a silky luster.
Description
## Characteristics Krasnoshteinite is a very rare mineral from the borate group. It forms aggregates resembling chalk or glass wool, composed of microscopic, acicular crystals. It typically occurs as white, radial or tangled aggregates, which are very brittle and soft to the touch. Due to the small size of its crystals, its features are rarely visible to the naked eye. ## Physical Properties This mineral is very soft, with a hardness of about 2 on the Mohs scale, meaning it can be scratched with a fingernail. It has a low density, approximately 2.02 g/cm³. The luster is most often silky for fibrous aggregates or dull and earthy for compact forms. It is translucent to opaque. ## Colors and Varieties Krasnoshteinite is a white or colorless mineral. No colored varieties or trade names are known. ## History and Name The mineral was officially recognized by the International Mineralogical Association (IMA) in 2012. Its name honors Arkady A. Krasnoshtein (1935–2007), a Russian geologist and specialist in lazurite deposits, who studied the area of the mineral's discovery. The type locality is the Malo-Bystrinskoe lazurite deposit in the Lake Baikal region of Russia. ## Uses Krasnoshteinite has no industrial applications. It is solely an object of scientific interest and is valued by collectors specializing in rare minerals and micromounts.
Diagnostic features
## Identification Krasnoshteinite is primarily identified based on its unique occurrence and mineral paragenesis. Characteristic features include white, very soft, and light aggregates with a silky or earthy luster. A key characteristic is its reaction to water – it dissolves. Final identification requires advanced analytical methods, such as X-ray diffraction (XRD). ## Distinguishing from Similar Minerals It can be confused with other white, secondary minerals with fibrous or earthy textures, such as shabynite or some zeolites. Differentiation in the field is practically impossible. Shabynite, often co-occurring with krasnoshteinite, is a magnesium borate, not aluminum, which can only be determined by chemical analysis. ## Crystal Forms It forms microscopic crystals with an acicular or hair-like habit. These crystals combine into tangled, fibrous masses, radial aggregates, or compact, chalk-like groupings.
Geological environment
## Genesis It is a secondary mineral, forming under specific geochemical conditions. It forms in hydrothermal alteration zones of carbonate rocks (marbles), in a boron- and chlorine-rich environment. Its formation is associated with the alteration of earlier minerals in lazurite deposits. ## Mineral Associations Krasnoshteinite occurs in association with other rare borate and chloride minerals. It most commonly co-occurs with shabynite, iowaite, ekaterinite, as well as calcite and dolomite, which form the host rock. ## Localities The only confirmed and well-documented locality for krasnoshteinite in the world is its type locality – the Malo-Bystrinskoe lazurite deposit, located on the Malaya Bystraya River, near Lake Baikal in Siberia, Russia.
Rarity
Extremely rare
Collector aspects
## Quality Criteria The quality of krasnoshteinite specimens is primarily assessed based on the richness and purity of the aggregates on the rock matrix. As it is a mineral for micromount collections, specimens with visible, even under a microscope, radial aggregates are more highly valued than compact, earthy masses. The presence of rare associated minerals on the same specimen also adds significant value. ## Popular Localities The only source of collector specimens is the Malo-Bystrinskoe deposit in Russia. This mineral is not known from any other localities worldwide, making it extremely desirable for collectors specializing in minerals from specific locations (so-called "locality collectors") and rare species.
Care and storage
## Cleaning Krasnoshteinite specimens are extremely delicate. They should only be dry-cleaned using a soft brush or a gentle stream of compressed air to remove dust. Absolutely avoid contact with water. ## What to Avoid The mineral is soluble in water. Contact with water, water vapor, and high humidity must be strictly avoided. It is very soft and brittle, so it must be protected from impacts, scratches, and vibrations. All chemicals and high temperatures should also be avoided. ## Storage It is recommended to store specimens in tightly sealed containers (e.g., "perky boxes") to protect them from moisture and mechanical damage. They should ideally be kept in stable conditions, away from heat sources and direct sunlight.