Sergeysmirnovite
Chemical formula: MgZn<sup>2+</sup><sub>2</sub>(PO<sub>4</sub>)<sub>2</sub>·4H<sub>2</sub>O
Sergeysmirnovite is an extremely rare, hydrated magnesium and zinc phosphate, forming colorless, acicular crystals in radial aggregates.
Description
## Characteristics Sergeysmirnovite is a hydrated zinc and magnesium phosphate. It forms characteristic radial or sheaf-like aggregates, composed of very small, thin, and flattened crystals. The size of the aggregates rarely exceeds 0.5 mm, classifying it as a typical micromineral. It is colorless and transparent, with a vitreous luster. ## Physical Properties The mineral is characterized by a vitreous luster and is transparent. Its Mohs hardness has not yet been determined. The density calculated based on the formula and unit cell parameters is 3.01 g/cm³. ## Colors and Varieties It is a colorless mineral. No colored or commercial varieties are distinguished. ## History and Name The mineral was officially approved by the International Mineralogical Association (IMA) in 2020. Its name honors Sergey Sergeyevich Smirnov (1894-1947), a Russian geologist and specialist in mineral deposits, academician of the USSR Academy of Sciences. ## Uses Due to its extreme rarity and microscopic crystal size, sergeysmirnovite has no practical application. It is solely an object of scientific interest and a valued acquisition for advanced systematic collections.
Diagnostic features
## Identification Amateur identification of the mineral is practically impossible. Certain identification requires advanced analytical methods, such as energy-dispersive spectroscopy (EDS) to determine chemical composition and X-ray diffraction (XRD) to confirm crystal structure. A visual clue within the typical locality is the radial habit of colorless aggregates. ## Distinguishing from Similar Minerals It can be confused with other colorless, secondary phosphates occurring in the same paragenesis, such as hopeite, scholzite, or parascholzite. Distinguishing it from these minerals based on visual characteristics is not possible and requires specialized equipment. ## Crystal Forms The crystals are thin, flattened, and elongated along the crystallographic a-axis. They occur as radial or sheaf-like aggregates, with diameters up to 0.5 mm.
Geological environment
## Genesis Sergeysmirnovite is a secondary mineral. It forms in the oxidation zone of cassiterite-sulfide deposits, crystallizing in small cavities and fissures in quartz. ## Mineral Associations It most commonly co-occurs with other phosphates, such as hopeite, phosphophyllite, parascholzite, stewartite, and scholzite. Cassiterite and quartz also accompany them. ## Localities The only confirmed occurrence of this mineral in the world is its type locality - the Kester deposit within the Arga-Ynnakh-Khaya granite massif, in the Sakha Republic (Yakutia), Russia.
Rarity
Extremely rare
Collector aspects
## Quality Criteria For micromineral collectors, the quality and aesthetics of the aggregates are paramount. Specimens with well-formed, clearly visible radial or sheaf-like crystal clusters, contrastingly set on a rock matrix, are most highly valued. The presence of other rare associated minerals on the same specimen adds additional value. ## Popular Localities All known collector specimens come from a single location in the world - the Kester deposit in Yakutia (Russia). This is simultaneously the only and most prized source of this mineral.
Care and storage
## Cleaning Extreme caution is advised. Cleaning specimens should be limited to gently removing dust with compressed air. Contact with water, ultrasonic cleaners, and any chemical agents should be strictly avoided. ## What to Avoid The mineral is sensitive to high temperatures, which can lead to dehydration (loss of water in the structure) and its destruction. It should be protected from acids and other aggressive chemicals. The fragility of the crystals requires protection from shocks and impacts. ## Storage Sergeysmirnovite specimens, as microminerals, should be stored exclusively in specialized, sealed "micromount" boxes, which protect them from dust, moisture, and mechanical damage.