Parahibbingite

Chemical formula: Fe₂+₂(OH)₃Cl

Parahibbingite is a very rare iron hydroxide chloride, forming microscopic, colorless to pale green crystals with a hexagonal structure.

## Characteristics Parahibbingite is a mineral from the halide group, chemically classified as an iron(II) hydroxide chloride. It occurs as very small, hexagonal crystals that rarely exceed fractions of a millimeter. It typically forms minute, prismatic or tabular crystals, as well as their radial aggregates. Due to its size, observation of visual features requires the use of a microscope. ## Physical Properties Parahibbingite crystals exhibit a vitreous to pearly luster on cleavage surfaces. They are transparent to translucent. The Mohs hardness is approximately 3.5, and the calculated density is 3.45 g/cm³. This mineral is brittle. ## Colors and Varieties Parahibbingite is usually colorless, sometimes taking on a pale green hue. No varieties have been distinguished. ## History and Name The name "parahibbingite" refers to its close relationship with hibbingite. The prefix "para-" refers to polymorphism, indicating that it is a hexagonal polymorph of hibbingite, which crystallizes in the orthorhombic system. It was approved as a new mineral by the International Mineralogical Association (IMA) in 1992. ## Applications Parahibbingite has no industrial applications. Its significance is purely scientific and collectible, although due to its microscopic size and rarity, it is primarily of interest to specialized collectors.

Properties

Mohs hardness: 3.5
Luster: Vitreous to pearly
Streak: White
Density: 3.45
Cleavage: Perfect on {0001}
Fracture: Uneven
Transparency: Transparent to translucent
Crystal system: Hexagonal

Diagnostic features

## Identification Identification of parahibbingite is possible almost exclusively through advanced laboratory methods, such as X-ray diffraction (XRD) or Raman spectroscopy. Visually, under microscopic conditions, small, colorless or pale green hexagonal crystals can be observed. Its instability upon contact with air and moisture is also a characteristic feature. ## Distinguishing from Similar Minerals Hibbingite is practically indistinguishable from parahibbingite without crystallographic analysis; they differ in their crystal system (orthorhombic for hibbingite, hexagonal for parahibbingite). Other similar, secondary iron minerals may have a comparable appearance, but definitive identification always requires specialized studies. ## Crystal Forms Parahibbingite forms hexagonal, prismatic or tabular crystals. They often occur as radial or irregular aggregates.

Geological environment

## Genesis Parahibbingite is a secondary mineral, forming under specific conditions. Its typical formation environment is fluid inclusions in ultramafic rocks, such as dunites, that have undergone serpentinization processes. It forms under strongly reducing conditions, in the presence of concentrated iron- and chlorine-rich brines. ## Mineral Associations This mineral coexists with hibbingite, magnetite, lizardite, brucite, chlorite, awaruite, and iron and nickel sulfides. It is often found within or surrounding olivine crystals. ## Localities The most important and well-documented parahibbingite localities worldwide include the Duluth Complex in Minnesota (USA), where it was discovered, and the Oktyabrskoye nickel-copper deposit in Siberia (Russia). It also occurs in ophiolites in Cyprus and in the Bushveld Complex in South Africa.

Rarity

Very rare

For collectors

## Quality Criteria For parahibbingite, collectible specimens are typically fragments of host rock containing microscopic crystals of this mineral. The most highly valued samples are those in which the crystals, despite their small size, are well-formed, create aggregates visible under a microscope, and are confirmed by analysis. The presence of associated minerals, such as hibbingite, can increase the scientific and collectible value of the specimen. ## Popular Localities The best-known specimens, though still rare on the market, come from the type locality in the Duluth Complex in Minnesota, USA, and from the Oktyabrskoye deposit in the Norilsk region of Russia.

Care and storage

## Cleaning Specimens containing parahibbingite should be handled with the utmost care. Due to the microscopic size of the crystals, mechanical cleaning is not recommended. If it is necessary to remove loose contaminants, compressed air can be used from a safe distance. ## What to Avoid Contact with water and chemicals must be strictly avoided, as the mineral is soluble in acids and unstable in humid environments. When exposed to air and moisture, it easily oxidizes and transforms into other iron compounds, losing its structure and appearance. It should be protected from high temperatures and direct sunlight. ## Storage Parahibbingite specimens must be stored in dry conditions, preferably in sealed containers (e.g., "perky box") away from moisture. It is advisable to place a desiccant, such as silica gel, in the container. Storage at a stable room temperature is crucial for maintaining the mineral's integrity.

Sources

IMA Mineral List (CNMNC)