Burpalite

Chemical formula: Na₂CaZr₄+(Si₂O₇)F₂

Burpalite is a rare zirconium, calcium, and sodium silicate, forming small, colorless to light brown crystals with a vitreous luster.

## Characteristics Burpalite is a complex silicate from the sorosilicate group, belonging to the wöhlerite group. Its chemical composition includes sodium, calcium, zirconium, and fluorine. It forms small, tabular or prismatic crystals, usually not exceeding a few millimeters in size. It most commonly occurs as single, well-formed crystals or small granular aggregates embedded in the host rock. It is a transparent to translucent mineral. ## Physical Properties This mineral has a hardness of 5.5 on the Mohs scale. It has a vitreous luster and a white streak. Its density is relatively high, approximately 3.35 g/cm³. The crystals exhibit good cleavage in one direction. ## Colors and Varieties Burpalite is typically colorless, white, gray, or light brown. No named color varieties or commercial varieties are distinguished. ## History and Name The mineral's name comes from the Burpala massif in Buryatia (Russia), where it was discovered and first described in 1991 by A.P. Khomyakov, L.I. Polezhaeva, and G.E. Cherepivskaya. It was approved by the International Mineralogical Association (IMA) in the same year. ## Applications Due to its rarity and small crystal size, burpalite has no industrial applications. It is solely an object of interest for collectors specializing in rare minerals and scientists studying agpaitic pegmatites.

Properties

Mohs hardness: 5.5
Luster: Vitreous
Streak: White
Density: 3.35
Cleavage: Good on {001}
Fracture: Uneven
Transparency: Transparent to translucent
Crystal system: Monoclinic

Diagnostic features

## Identification Amateur identification of burpalite is very difficult due to its resemblance to other silicates found in the same environment. Its characteristic tabular habit, vitreous luster, and occurrence in a specific type of rock – alkaline pegmatites – are distinctive. Definitive identification requires advanced analytical methods, such as X-ray diffraction (XRD) or chemical microanalysis (EDS/WDS). ## Distinguishing from Similar Minerals Burpalite can be confused with other minerals from the wöhlerite group, such as wöhlerite itself or låvenite, which have a similar appearance and occur in the same parageneses. Distinguishing them based on visual characteristics is practically impossible and requires specialized laboratory tests. ## Crystal Forms Burpalite crystallizes in the monoclinic system. It forms flattened, tabular crystals with hexagonal or octagonal outlines, as well as short prismatic crystals. It also occurs as granular aggregates.

Geological environment

## Genesis Burpalite is a magmatic mineral, crystallizing in the late stages of the formation of nepheline-syenite pegmatites (so-called agpaitic pegmatites). It forms in an environment rich in alkaline elements (sodium, potassium) and rare elements, such as zirconium. ## Mineral Associations This mineral co-occurs with other rare minerals typical of alkaline pegmatites. Its most common associations include microcline, nepheline, eudialyte, loparite-(Ce), lorenzenite, murmanite, and lamprophyllite. ## Localities The most important and type locality for burpalite is the Burpala alkaline massif in the northern Baikal region of Buryatia, Russia. This is currently the only confirmed and well-documented locality for this mineral worldwide.

Rarity

Very rare

For collectors

## Quality Criteria The collector's appeal of burpalite primarily depends on the quality and size of the well-formed crystals. The most valued are sharp, well-formed, transparent crystals that stand out clearly from the host rock (matrix). The presence of rare associated minerals also enhances the scientific and aesthetic value of the specimen. ## Popular Localities The only source of collector specimens is the Burpala massif in Russia. Specimens from this locality are highly sought after by specialized collectors of rare minerals and microminerals.

Care and storage

## Cleaning Burpalite specimens should be cleaned very carefully, using a soft brush to remove dust. If necessary, distilled water can be used, but prolonged soaking should be avoided. Always allow the specimen to dry completely at room temperature. ## What to Avoid Avoid contact with acids and other aggressive chemicals, which can damage the mineral's surface. It should not be cleaned in ultrasonic cleaners. The mineral is sensitive to sudden temperature changes. ## Storage It is recommended to store burpalite specimens in separate, padded collector boxes to prevent scratches from harder minerals. It should be protected from dust and moisture. Due to the small size of its crystals, it is ideally suited for micromineral collections.

Sources

IMA Mineral List (CNMNC)