Heideite

Chemical formula: (Fe₂+,Cr₂+)₁.₁₅(Ti₃+,Fe₂+)₂S₂-₄

Heideite is an extremely rare iron, chromium, and titanium sulfide, known exclusively from a single meteorite found in India.

## Characteristics Heideite is a mineral with a metallic luster, occurring as extremely small, irregular grains and aggregates not exceeding 0.5 mm in size. It has only been observed in polished sections under a microscope, where it forms inclusions within other meteoritic minerals. Its color in reflected light is described as creamy white with a slight pinkish tint. ## Physical Properties Due to the extremely small size of the grains, most physical properties of heideite have not been precisely determined. Hardness is estimated at approximately 4 on the Mohs scale. The mineral is opaque and has a metallic luster. The density calculated based on the chemical formula and unit cell parameters is 4.11 g/cm³. ## History and Name The mineral was discovered and described in 1974 by a research team led by Ahmed El Goresy. The name "heideite" was given in honor of Fritz Heide (1891-1973), a German mineralogist and cosmochemist, professor at the University of Jena, for his contributions to meteorite research.

Properties

Mohs hardness: 4
Luster: Metallic
Density: 4.11
Cleavage: None
Fracture: Uneven
Transparency: Opaque
Crystal system: Monoclinic

Diagnostic features

## Identification Identification of heideite is only possible using advanced laboratory techniques, such as reflected light ore microscopy and chemical analysis using an electron microprobe (EDS/WDS). Its characteristic features include a creamy white color with a pinkish tint and a specific chemical composition. ## Differentiation from Similar Minerals Under the microscope, it may resemble other meteoritic sulfides such as troilite or daubréelite. Definitive differentiation requires chemical composition analysis, especially confirmation of the presence of titanium, iron, and chromium in appropriate proportions. ## Crystal Forms Heideite forms exclusively anhedral (irregular) grains and aggregates, without developed crystal faces.

Geological environment

## Genesis Heideite is a mineral of extraterrestrial origin. It formed under strongly reducing conditions within the parent body of the asteroid from which the Bustee meteorite originated. It crystallized at high temperatures as one of the primary sulfides. ## Mineral Associations This mineral occurs in close association with other rare meteoritic minerals. Most commonly, it forms inclusions in niningerite, and also co-occurs with daubréelite, oldhamite, troilite, osbornite, and enstatite. ## Localities The only confirmed locality for heideite in the world is the Bustee meteorite. This is an enstatite chondrite (aubrite) that fell in 1852 near Gorakhpur in Uttar Pradesh, India.

Rarity

Extremely rare

For collectors

## Quality Criteria Heideite does not occur as standalone collector specimens. Its value is purely scientific. The only way to possess this mineral in a collection is to acquire a fragment of the Bustee meteorite in which its presence has been analytically confirmed. In such a case, the value of the specimen is determined by the size and quality of the meteorite itself, rather than by the visual characteristics of heideite.

Care and storage

## Cleaning Due to its occurrence exclusively as microscopic inclusions in meteorites, individual heideite specimens are not available and do not require cleaning. ## What to Avoid Meteorite specimens containing heideite should be protected from moisture and aggressive chemicals, which could damage the surrounding minerals. ## Storage Fragments of the Bustee meteorite should be stored under stable conditions, preferably in a dry environment (e.g., in a container with a desiccant), to prevent the oxidation of sulfides and other minerals.

Sources

IMA Mineral List (CNMNC)