Zolenskyite

Chemical formula: Fe₂+Cr₃+₂S₂-₄

Zolenskyite is an extremely rare iron chromium sulfide, discovered in a meteorite and named after the cosmic matter researcher, Michael E. Zolensky.

## Characteristics Zolenskyite is a mineral with a metallic luster, occurring as extremely small, submicron grains, typically less than 300 nanometers in size. It is observed as inclusions within other sulfide minerals, such as troilite. Due to the extremely small size of its crystals, its visual characteristics cannot be assessed with the naked eye, and identification requires advanced analytical techniques, such as scanning electron microscopy (SEM) and electron diffraction. ## Physical Properties As an opaque mineral, zolenskyite is characterized by a metallic luster. Its hardness, density, and other physical properties have not been precisely measured due to the microscopic size of the grains. The density calculated based on its chemical formula and crystal structure is approximately 4.36 g/cm³. ## Colors and Varieties The mineral is opaque, and under a microscope in reflected light, it appears gray. No varieties have been distinguished. ## History and Name Zolenskyite was officially recognized as a new mineral by the International Mineralogical Association (IMA) in 2017 (IMA2017-003). Its name honors Dr. Michael E. Zolensky, an American scientist from NASA Johnson Space Center, for his contributions to the study of meteorites and cosmic dust. The mineral was discovered in the Indarch meteorite, which fell in Azerbaijan in 1891. ## Uses Zolenskyite has no commercial or industrial applications. Its significance is purely scientific, providing information about the processes of mineral formation in extraterrestrial conditions, particularly in meteorite parent bodies.

Properties

Luster: Metallic
Density: 4.36
Transparency: Opaque
Crystal system: Monoclinic

Diagnostic features

## Identification Identification of zolenskyite is impossible without specialized equipment. It requires chemical analysis using an electron microprobe (EDS/WDS) to confirm its composition (iron, chromium, sulfur) and structural studies using electron diffraction in a transmission electron microscope (TEM). It occurs as submicron grains within other sulfides. ## Distinguishing from Similar Minerals Zolenskyite is a member of the daubréelite group and is its ferrous (Fe²⁺) analog. It differs from daubréelite (Fe²⁺Cr³⁺₂S₄) in its crystal structure (monoclinic vs. isometric). From other sulfides coexisting in meteorites, such as troilite (FeS) or pentlandite ((Fe,Ni)₉S₈), it is distinguished by its high chromium content, confirmed by chemical analysis. ## Crystal Forms The mineral forms exclusively anhedral (irregular), submicron grains, most often occurring as inclusions in troilite. No distinct, well-formed crystal habits have been observed.

Geological environment

## Genesis Zolenskyite is a mineral of extraterrestrial origin. It forms as a result of processes occurring within meteorite parent bodies under strongly reducing conditions (with low oxygen availability). Its presence in the Indarch meteorite (an EH4 enstatite chondrite) indicates crystallization from a chromium- and iron-rich sulfide phase during thermal metamorphism or metasomatism in the parent asteroid. ## Mineral Associations This mineral occurs in close association with other meteoritic sulfides. Most often, it is found as inclusions in troilite (FeS). It also coexists with daubréelite (FeCr₂S₄), niningerite ((Mg,Fe)S), oldhamite (CaS), and perryite ((Ni,Fe)₅(Si,P)₂). ## Localities The only confirmed locality of zolenskyite in the world is its type locality – the Indarch meteorite. This is an enstatite chondrite that fell on April 7, 1891, near the town of Şuşa in Azerbaijan.

Rarity

Extremely rare

For collectors

## Quality Criteria Zolenskyite does not occur as collector specimens in the traditional sense. Its value is purely scientific and related to its presence in a specific, rare type of meteorite. For research institutions and specialized meteorite collectors, the value lies in the fragment of the Indarch meteorite itself, in which the presence of this mineral has been analytically confirmed. It is not evaluated based on aesthetics, color, or form. ## Popular Localities The only source of this mineral is the Indarch meteorite. Fragments of this historic fall are found in institutional and museum collections worldwide, including the Natural History Museum in Vienna and the Center for Meteorite Studies at Arizona State University.

Care and storage

## Cleaning Specimens containing zolenskyite (typically meteorite fragments) should not be wet-cleaned. Any contaminants should be removed dry, using compressed air or a very soft brush. ## What to Avoid Avoid contact with water, chemicals, and humid air, as sulfides, especially those found in meteorites, are susceptible to oxidation and decomposition. Do not heat the specimen or subject it to sudden temperature changes. ## Storage Meteorite fragments containing zolenskyite must be stored under controlled, low-humidity conditions. It is best to use sealed containers (so-called "perky boxes") with a desiccant, such as silica gel. Store away from direct sunlight and heat sources.

Sources

IMA Mineral List (CNMNC)