Parasibirskite

Chemical formula: CaHBO<sub>3</sub>

Parasibirskite is a rare calcium borate, forming tiny, colorless to white crystals and aggregates, closely related to sibirskite.

## Characteristics Parasibirskite is a mineral from the borate group, chemically a hydrated calcium borate. It occurs as very small, tabular or bladed crystals, rarely exceeding 0.5 mm in length. Most often, it forms rosette-like or spherulitic aggregates, as well as veins and crusts. It is a colorless to white mineral with a vitreous or pearly luster. ## Physical Properties This mineral is characterized by a hardness of approximately 3.5 on the Mohs scale. Its crystals exhibit perfect cleavage in one direction. It is transparent to translucent. Due to the small size of the crystals, accurate determination of many physical properties is difficult. ## History and Name Parasibirskite was first described in 1994 by S.V. Malinko, N.V. Chukanova, A.V. Zaval'yanova, and V.V. Khrupenkova. Its name refers to its structural and chemical similarity to sibirskite, with which it is dimorphic (having the same chemical composition but a different crystal structure). The name comes from the Greek prefix "para-" meaning "beside" or "near" and the mineral name sibirskite.

Properties

Mohs hardness
3.5
Luster
Vitreous, Pearly
Streak
White
Density
2.55
Cleavage
Perfect on {010}
Fracture
Uneven
Transparency
Transparent to translucent
Crystal system
Monoclinic

Diagnostic features

## Identification Identifying parasibirskite under amateur conditions is practically impossible due to its rarity and small crystal size. Recognition requires advanced analytical methods, such as X-ray diffraction (XRD) or spectroscopy. Visually, it is characterized by white, pearly-lustered aggregates of tiny crystals. ## Distinguishing from similar minerals Parasibirskite is dimorphic with sibirskite. Distinguishing these two minerals without specialized equipment is impossible. It can also be confused with other white borates or carbonates occurring in similar parageneses, such as calcite or colemanite. Reaction with hydrochloric acid (vigorous effervescence) distinguishes it from colemanite, but not from calcite. Final differentiation requires laboratory analysis. ## Crystal forms It forms very small, thin, tabular crystals with a hexagonal or rhombic outline, often elongated. These crystals usually group into rosette-like, radial, or spherulitic aggregates.

Geological environment

## Genesis Parasibirskite is a hydrothermal mineral, forming at low temperatures. It forms in magnesian skarns, which developed at the contact of granitoid intrusions with carbonate rocks (limestones and dolomites). ## Mineral associations It most often co-occurs with sibirskite, calcite, dolomite, fluoborite, kotoite, ludwigite, szaibelyite, and minerals from the serpentine group. ## Localities As a very rare mineral, it is known from only a few localities worldwide. The type locality is the Titovskoye boron deposit on the Tas-Khayakhtakh Ridge in Yakutia (Sakha Republic), Russia. Its occurrence has also been confirmed at the Fuka mine in Okayama Prefecture, Japan, and in the Coroana and Brosso mines in Italy.

Rarity

Very rare

For collectors

## Quality criteria Due to its extreme rarity and microscopic crystal sizes, every analytically confirmed specimen of parasibirskite is valuable to specialized rare species collectors. The most highly prized specimens are those that show well-formed, even if tiny, crystalline aggregates, clearly distinct from the host rock. Precise documentation and locality confirmation are crucial. ## Popular localities The most "classic" specimens, though still microscopic, come from the type locality in Russia (Titovskoye deposit) and from the Fuka mine in Japan.

Care and storage

## Cleaning Due to the small size and fragility of the crystals, mechanical cleaning is not recommended. If necessary, compressed air can be used to remove dust. Contact with water, especially deionized water, can be risky due to potential solubility. ## What to avoid Contact with acids, which rapidly dissolve the mineral, must be strictly avoided. Ultrasonic cleaning, steam cleaning, and immersion in water should also be avoided. Store away from moisture. ## Storage Parasibirskite specimens are typically small and fragile, so it is best to store them in specialized micromount boxes, which protect them from mechanical damage and dust. Dry storage conditions should be ensured.

Sources

Read more