Svyatoslavite

Chemical formula: CaAl₂Si₂O₈

Svyatoslavite is a rare mineral from the feldspar group, a polymorphic variety of anorthite, found as small, colorless crystals in altered volcanic rocks.

## Characteristics Svyatoslavite is a mineral belonging to the feldspar group, being a high-temperature, orthorhombic variety of anorthite. It occurs in the form of very small, tabular or lath-like crystals, which rarely exceed 0.5 mm in length. It usually forms colorless, transparent grains with a vitreous luster, often intergrown into small aggregates. ## Physical Properties The mineral is characterized by a hardness of approximately 6 on the Mohs scale. Its density is similar to other feldspars, around 2.73 g/cm³. Crystals exhibit perfect cleavage in one direction. ## Colors and Varieties Svyatoslavite is usually colorless and transparent. No colored varieties or trade names are known. ## History and Name The mineral is named in honor of Svyatoslav Fyodorovich Richterov (1915–1997), a Russian geologist and petrologist, specialist in volcanism. The mineral was first described in 1989 after being found in the Chelyabinsk Oblast in the Urals, Russia. ## Applications Due to its rarity and small crystal size, svyatoslavite has no industrial application and is solely an object of scientific interest and a collector's item for specialized micromineral collectors.

Properties

Mohs hardness
6
Color
Colourless
Luster
Vitreous
Streak
white
Density
2.695
Cleavage
Poor on {100}
Fracture
Conchoidal
Transparency
Transparent
Crystal system
Monoclinic

Diagnostic features

## Identification Identification of svyatoslavite is extremely difficult and practically impossible without advanced analytical methods, such as X-ray diffraction (XRD) or chemical analysis (EDS/WDS). Under collecting conditions, identification relies on a label from a confirmed locality. Visually, it is indistinguishable from many other colorless microminerals. ## Distinguishing from Similar Minerals It can be confused with other polymorphic varieties of anorthite (dmisteinbergite, svetlozarite) and other colorless feldspars or zeolites occurring in similar parageneses. Certain differentiation requires specialized laboratory tests. ## Crystal Forms It forms very small, thin, tabular crystals with a rectangular or square outline, often with truncated corners. It occurs as single crystals or small, radial aggregates.

Geological environment

## Genesis Svyatoslavite forms under high-temperature and low-pressure conditions. It is a product of the alteration of carbonate xenoliths (fragments of sedimentary rocks) within hot basaltic lava. It forms in the contact zone between the xenolith and the lava. ## Mineral Associations This mineral coexists with other contact minerals, such as gehlenite, larnite, perovskite, spinel, and other rare varieties of anorthite. ## Localities The most important and type locality for this mineral is in a brown coal mine near the city of Korkino in the Chelyabinsk Oblast, Southern Urals, Russia. It has also been identified in the Halamish volcanic complex in Israel.

Rarity

Very rare

For collectors

## Quality Criteria As a micromineral, specimens with well-formed, sharp, and undamaged crystals that are clearly visible on the rock matrix are most highly valued. Due to its colorless nature, the form and transparency of the crystals, as well as the abundance of occurrence on a given rock fragment, are crucial. Contrast with a darker matrix enhances aesthetic appeal. ## Popular Localities The only source of collector specimens is the type locality in Korkino in the Russian Urals.

Care and storage

## Cleaning Specimens should be cleaned exclusively with compressed air to remove dust. Due to the extreme rarity and small size of the crystals, contact with water and any chemical agents should be avoided. ## What to Avoid Avoid ultrasonic cleaners, chemicals, acids, and sudden temperature changes. The mineral is brittle and susceptible to mechanical damage. ## Storage Micromineral specimens should be stored in specialized "micromount" boxes that protect them from dust, shocks, and mechanical damage. Exposure to moisture should be avoided.

External references

Sources

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