Stanevansite

Chemical formula: Mg(C₂H₃O₃)¹⁻₂(H₂O)₂

Stanevansite is a rare organic mineral, hydrated magnesium glycolate, forming colorless, acicular crystals.

## Characteristics Stanevansite is an organic mineral, specifically hydrated magnesium glycolate. It occurs as very small, colorless, acicular or bladed crystals, which typically form radial aggregates or disordered, cotton-like masses. Individual crystals are flexible and can reach up to 2 mm in length, but their thickness rarely exceeds a few micrometers. ## Physical Properties Stanevansite crystals are characterized by a silky luster. They are transparent and colorless. Due to the small size and delicacy of the crystals, determining many physical properties, such as hardness or density, is difficult. The density calculated from crystallographic data is approximately 1.52 g/cm³. ## History and Name The mineral was named in honor of Howard Stanley Evans Jr. (1919-2002), an American crystallographer and chemist from the United States Geological Survey, in recognition of his contributions to mineralogy and crystal chemistry. It was approved by the International Mineralogical Association (IMA) in 2000. ## Uses Stanevansite has no practical applications and is solely of scientific and collecting interest as a unique organic mineral.

Properties

Mohs hardness
1.5-0
Color
colourless
Luster
Silky
Streak
White
Density
1.69
Cleavage
{100}
Transparency
Transparent
Crystal system
Monoclinic

Diagnostic features

## Identification Field identification of stanevansite is practically impossible. The mineral is recognized by its unique morphology – very thin, acicular crystals forming radial or tangled aggregates. Final confirmation requires advanced analytical methods, such as X-ray diffraction (XRD) and spectroscopy. ## Differentiation from Similar Minerals Stanevansite can be confused with other secondary organic minerals or sulfates forming acicular efflorescences, such as gypsum or epsomite. Differentiation with the naked eye is impossible. The key factors are the occurrence environment (burn sites) and chemical analysis. ## Crystal Forms Crystals are strongly elongated in the form of needles or blades, often flattened. They form radial, stellate aggregates or haphazardly tangled masses resembling felt or cotton.

Geological environment

## Genesis Stanevansite is a mineral of anthropogenic origin. It forms as a result of reactions between solutions derived from the decomposition of organic matter (in this case, ethylene glycol, a component of antifreeze) and magnesium oxide (periclase) at high temperatures. Its formation is observed on concrete fragments within coal fire waste heaps. ## Mineral Associations This mineral occurs in association with periclase, calcite, anhydrite, magnesite, and other rare organic minerals such as hoganite and paceite. ## Localities The only known locality of stanevansite in the world (type locality) is a mine dump near Scranton, Pennsylvania, USA. This is a site of a former coal fire.

Rarity

Extremely rare

For collectors

## Quality Criteria The quality of a stanevansite specimen is assessed based on the size and richness of crystal aggregates on the rock matrix. The most desirable specimens are those with well-formed, radial clusters of acicular crystals, clearly visible against a contrasting matrix. Due to its rarity, any authentic specimen is valuable. ## Popular Localities The only source of specimens is the historical type locality in Scranton, Pennsylvania, USA. Material from this location is extremely difficult to obtain.

Care and storage

## Cleaning Due to the extreme delicacy and small size of the crystals, mechanical cleaning (even with a soft brush) is highly risky and not recommended. Specimens should be protected from dust. ## What to Avoid Contact with water and other liquids, which can dissolve or damage the delicate crystals, must be absolutely avoided. The mineral is sensitive to changes in temperature and humidity. It should be protected from direct sunlight. ## Storage It is recommended to store specimens in closed, stable containers (so-called "micromount boxes") that protect against dust, humidity, and mechanical damage. Display should be carried out under controlled conditions.

External references

Sources

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