Paralabuntsovite-Mg

Chemical formula: Na₈K₈Mg₄Ti₄+₁₆(Si₄O₁₂)₈(O,OH)₁₆·₂₀-₂₄H₂O

A rare mineral from the labuntsovite group, forming small, prismatic crystals with a vitreous luster, found in alkaline massifs.

## Characteristics Paralabuntsovite-Mg is a complex silicate of titanium, sodium, potassium, and magnesium, belonging to the labuntsovite group. It forms elongated, prismatic or acicular crystals, which rarely exceed a few millimeters in length. They usually occur as radial or tangled aggregates in small rock cavities. Crystals are most often colorless, white, or yellowish and are characterized by a vitreous luster. ## Physical Properties This mineral has a hardness of about 6 on the Mohs scale. Its crystals exhibit a vitreous luster, and on fracture surfaces, it can be greasy. It is a transparent to translucent mineral. The calculated density is approximately 2.92 g/cm³. ## Colors and Varieties Paralabuntsovite-Mg occurs in a limited color range. The most common specimens are colorless, white, pale yellow, or cream. No named varieties have been distinguished. ## History and Name The mineral's name refers to its connection with the paralabuntsovite structure and to the dominant magnesium (Mg) in its composition. It was described as a new mineral in 2002 by N.V. Chukanov, I.V. Pekov, A.E. Zadov, V.A. Zaitsev, and N.N. Kononkova based on material from the Khibiny Massif in Russia.

Properties

Mohs hardness: 6
Luster: Vitreous
Streak: White
Density: 2.92
Cleavage: Good on {100}
Fracture: Uneven
Transparency: Transparent to Translucent
Crystal system: Monoclinic

Diagnostic features

## Identification Amateur identification of paralabuntsovite-Mg is very difficult and usually requires advanced analytical methods, such as spectroscopy or X-ray diffraction (XRD). Preliminary identification is based on the characteristic form of prismatic or acicular crystals, their occurrence in cavities of alkaline rocks, and co-occurrence with other rare minerals. ## Distinguishing from Similar Minerals This mineral is practically impossible to distinguish with the naked eye from other members of the labuntsovite group (e.g., labuntsovite-Mn, kuzmenkoite-Mn) and from some zeolites (e.g., natrolite), with which it can form similarly shaped aggregates. Certain differentiation requires chemical analysis to determine the dominant elements. ## Crystal Forms Paralabuntsovite-Mg forms elongated, prismatic crystals with a nearly square cross-section. They often occur as acicular, radial aggregates or tangled clusters filling small fissures and vugs in the host rock.

Geological environment

## Genesis It is a hydrothermal mineral, crystallizing in the late stages of the evolution of nepheline syenite pegmatites and in hydrothermal veins cutting alkaline rocks. It forms in an environment rich in sodium, potassium, titanium, and silicon. ## Mineral Associations Paralabuntsovite-Mg co-occurs with a wide range of minerals typical of alkaline pegmatites. The most common associations include aegirine, natrolite, microcline, nepheline, lorenzenite, eudialyte, and other minerals from the labuntsovite group. ## Localities The most important and well-documented localities for this mineral are in Russia, in the ultra-alkaline massifs of the Kola Peninsula. The type locality is Mount Khibiny (Khibiny Massif), as well as the Lovozero Massif (e.g., Mount Alluaiv, Karnasurt).

Rarity

Rare

For collectors

## Quality Criteria The collector's appeal of paralabuntsovite-Mg specimens primarily depends on the richness and development of the crystals. Most valued are specimens with clearly formed, transparent crystals creating aesthetic, radial aggregates on a contrasting rock matrix. Due to the small size of the crystals, specimens suitable for viewing under magnification (so-called microminerals) are standard. ## Popular Localities The vast majority, if not all, specimens available on the collector's market come from the Khibiny and Lovozero Massifs on the Kola Peninsula in Russia. These are classic and the most important localities for the entire labuntsovite group.

Care and storage

## Cleaning Cleaning with only a soft brush is recommended to remove dust. The use of water, especially with detergents, is not advisable due to the mineral's potential sensitivity and the fragility of its crystals. ## What to Avoid Avoid contact with all chemicals, including acids and strong bases. The crystals are brittle and susceptible to mechanical damage, so ultrasonics should be avoided. Do not heat or expose to rapid temperature changes. ## Storage Specimens should be stored in stable conditions, away from dust and direct sunlight. The safest way is to place them in a sealed display box or cabinet, which protects the delicate crystals from damage.

Sources

IMA Mineral List (CNMNC)