Stepanovite

Chemical formula: NaMgFe<sup>3+</sup>((C<sub>2</sub>)<sup>6+</sup>O<sub>4</sub>)<sub>3</sub>·9H<sub>2</sub>O

Stepanovite is an extremely rare organic mineral, a hydrated sodium, magnesium, and iron oxalate, forming characteristic hexagonal crystals of a yellow-green color.

## Characteristics Stepanovite is a complex, hydrated sodium, magnesium, and iron oxalate. It occurs as well-formed, hexagonal crystals with a tabular or prismatic habit, reaching up to 1 cm. The crystals are usually transparent to translucent and exhibit an intense, lemon-yellow or yellow-green color. It is a very delicate mineral, sensitive to environmental conditions. ## Physical Properties Stepanovite is characterized by very low hardness, approximately 2 on the Mohs scale, meaning it can be scratched with a fingernail. It has a vitreous luster and is light, with a density close to 1.63 g/cm³. It is brittle and easily damaged mechanically. ## Colors and Varieties This mineral occurs in uniform, characteristic shades from lemon-yellow to yellow-green. No color varieties or commercial varieties are distinguished. ## History and Name Stepanovite was discovered in 1953 in brown coal deposits in the Lena River region of Siberia (Russia). Its name commemorates the Russian geologist and mineralogist, Pavel Ivanovich Stepanov (1880–1947), a researcher of coal deposit geology. ## Uses Due to its extreme rarity, small crystal size, and high sensitivity to external conditions, stephanovite has no industrial application. It is solely an object of scientific interest and a valuable acquisition for specialized collectors of rare minerals.

Properties

Mohs hardness
2
Luster
Vitreous
Streak
Light yellow
Density
1.63
Cleavage
Perfect on {0001}
Fracture
Conchoidal
Transparency
Transparent to translucent
Crystal system
Hexagonal

Diagnostic features

## Identification Stepanovite is recognizable by its characteristic, intense yellow-green color, hexagonal crystal form, and very low hardness. A key diagnostic feature is its water solubility. Its occurrence in brown coal deposits is also a strong indicator. ## Distinguishing from Similar Minerals It can be confused with other rare oxalates, such as Zhemchuzhnikovite, which has a similar genesis and color but crystallizes in the trigonal system. Other yellow secondary minerals, like native sulfur, have a completely different genesis, odor, and are not water-soluble. ## Crystal Forms It forms well-developed, hexagonal crystals with a tabular or short-prismatic habit. It occurs as single crystals or in small aggregates growing on a substrate.

Geological environment

## Genesis Stepanovite is a mineral of organic origin, forming under specific conditions within brown coal deposits. Its formation is likely associated with the prolonged action of solutions rich in oxalic acid (derived from the decomposition of plant matter) on clay minerals and groundwater containing sodium, magnesium, and iron, under permafrost conditions. ## Mineral Associations It most often co-occurs with other rare oxalates, such as Zhemchuzhnikovite, as well as with Calcite, Gypsum, and clay minerals. These minerals form in the same specific geological environment. ## Localities This is an extremely rare mineral. Apart from the type locality in the Lena Basin in Siberia (Russia), its occurrence has only been confirmed in the Radbod coal mine in Hamm, North Rhine-Westphalia (Germany).

Rarity

Extremely rare

For collectors

## Quality Criteria The most highly valued specimens are those with well-formed, sharp, and undamaged crystals of intense, pure color. Transparency and crystal size are important – any specimen with crystals exceeding a few millimeters is considered exceptional. A contrasting matrix also enhances visual and collector value. ## Popular Localities The vast majority of the best quality specimens come from the discovery site in the Lena Basin in Siberia. However, these are practically unavailable on the collector's market. Specimens from the German Radbod mine, though also very rare, occasionally appear in circulation.

Care and storage

## Cleaning Stepanovite specimens should absolutely not be cleaned wet. The mineral is water-soluble. Only very careful dust removal with a soft brush or a stream of compressed air from a distance is permissible. ## What to Avoid Avoid contact with water, water vapor, and all chemicals. The mineral is sensitive to elevated temperatures, which can lead to its dehydration and destruction. It should be protected from direct sunlight and high air humidity. ## Storage Stepanovite requires storage in controlled, low-humidity conditions. It is best kept in a sealed, airtight container (a "perky box") with a desiccant (e.g., silica gel). It should be displayed away from heat and light sources.

Sources

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