Parakuzmenkoite-Fe

Chemical formula: (K,Ba)₈Fe₂+₄Ti₄+₁₆(Si₄O₁₂)₈(OH,O)₁₆·₂₀-₂₈H₂O

Parakuzmenkoite-Fe is a very rare mineral from the cyclosilicate group, forming small, brown crystals with a vitreous luster.

## Characteristics Parakuzmenkoite-Fe is a complex cyclosilicate of titanium, iron, and potassium, belonging to the kuzmenkoite group. It forms very small, tabular or lath-like crystals, rarely exceeding 1 mm in length. They usually occur as radial or chaotic aggregates. It is a transparent to translucent mineral with a vitreous luster. ## Physical Properties The mineral is characterized by a hardness of approximately 5 on the Mohs scale. Its density is slightly higher than quartz, at about 2.85 g/cm³. Crystals exhibit perfect cleavage in one direction. ## Colors and Varieties Parakuzmenkoite-Fe occurs in shades of brown – from light brown and yellowish-brown to reddish-brown. No varieties have been distinguished. ## History and Name The mineral's name refers to its chemical composition, indicating the dominance of iron (Fe) at a specific crystallographic site, and its structural relationship to kuzmenkoite. It was approved as a new mineral species by the International Mineralogical Association (IMA) in 2001. It was described based on material from the Khibiny Massif in Russia. ## Uses Parakuzmenkoite-Fe has no industrial application. It is of purely scientific and collector's interest as a very rare mineral.

Properties

Mohs hardness: 5
Luster: Vitreous
Streak: Light brown
Density: 2.85
Cleavage: Perfect on {001}
Fracture: Uneven
Transparency: Transparent to translucent
Crystal system: Monoclinic

Diagnostic features

## Identification Amateur identification of parakuzmenkoite-Fe is practically impossible. It requires advanced analytical methods such as X-ray diffraction (XRD) and chemical microanalysis (EDS/WDS) to confirm its composition and structure. Preliminary identification is based on the characteristic form of small, brown, tabular crystals in a specific geological environment. ## Distinguishing from Similar Minerals It can be confused with other rare titanosilicates from alkaline massifs, such as kuzmenkoite-Mn, labuntsovite-Mn, elpidite, or lorenzenite. Differentiation requires specialized laboratory tests. ## Crystal Forms Crystals are thin-tabular, elongated, with a rectangular cross-section. They usually form radial or chaotic aggregates and clusters. Single, well-formed crystals are rare.

Geological environment

## Genesis Parakuzmenkoite-Fe is a hydrothermal mineral, crystallizing in the late stages of evolution of nepheline-syenite pegmatites within alkaline massifs. It forms in cavities and fissures within these rocks. ## Mineral Associations It most commonly co-occurs with minerals such as microcline, nepheline, aegirine, natrolite, analcime, lorenzenite, eudialyte, and other rare titano- and zirconosilicates typical of agpaitic pegmatites. ## Localities The only confirmed and well-documented occurrences of parakuzmenkoite-Fe worldwide are in the ultra-alkaline massifs of the Kola Peninsula in Russia. These are primarily the Khibiny Massif (Oleniy Ruchey mine) and the Lovozero Massif (Karnasurt Mountain).

Rarity

Very rare

For collectors

## Quality Criteria The most highly valued specimens of parakuzmenkoite-Fe are those with well-formed, sharply terminated crystals forming aesthetic, radial aggregates on a contrasting rock matrix (e.g., on white analcime or natrolite). Due to the small size of the crystals, their good visibility and abundance on the specimen are crucial. The color, although usually brown, can be a differentiating factor if it is intense and vibrant. ## Popular Localities By far the most known and prized specimens come from the discovery locality – the Oleniy Ruchey mine in the Khibiny Massif on the Kola Peninsula in Russia. This is the classic and practically only commercially available locality for this mineral.

Care and storage

## Cleaning Specimens should be cleaned very carefully, using a soft brush to remove dust. Due to the presence of potassium and water in its structure, prolonged contact with water, and especially with chemicals, should be avoided. ## What to Avoid Avoid ultrasonic cleaners, chemical agents, acids, and bases. The mineral is sensitive to high temperatures, which can lead to dehydration and destruction of its structure. Protect it from direct sunlight. ## Storage It is recommended to store specimens in stable conditions, in closed display boxes, to protect them from dust, mechanical damage, and sudden changes in humidity and temperature.

Sources

IMA Mineral List (CNMNC)