Swedenborgite

Chemical formula: NaBe₄Sb⁵⁺O₇

Swedenborgite is a very rare sodium beryllium antimonate, distinguished by its exceptional hardness and vitreous luster.

## Characteristics Swedenborgite is an extremely rare mineral from the antimonate group, chemically classified as a sodium beryllium antimonate. It occurs in the form of small, hexagonal, tabular or prismatic crystals, rarely exceeding a few millimeters in size. It is most commonly found as single, well-formed crystals embedded in a calcite matrix. It is characterized by a strong, vitreous luster, and its transparency makes it an attractive micromount mineral. ## Physical Properties This mineral is characterized by very high hardness, measuring 8 on the Mohs scale, which is a value similar to topaz. Its luster is intensely vitreous. It is a relatively dense mineral, with a specific gravity of approximately 4.28 g/cm³. The crystals are transparent. ## Colors and Varieties Swedenborgite is most often colorless or takes on delicate shades from pale yellow (wine yellow), through honey-yellow, to light yellow. In transmitted light, it is colorless. No named varieties of this mineral are distinguished. ## History and Name The mineral was discovered and described in 1924. Its name honors Emanuel Swedenborg (1688–1772), a Swedish scientist, philosopher, and theologian, who was also an assessor in the Swedish Royal Board of Mines and authored works on metallurgy and mining. ## Uses Due to its extreme rarity and small crystal size, swedenborgite has no industrial applications. It is solely an object of scientific interest and a prized acquisition for specialized collectors of rare minerals and micromount specimens.

Properties

Mohs hardness
8
Luster
Vitreous
Streak
White
Density
4.285
Cleavage
On {0001}, distinct.
Fracture
Sub-Conchoidal
Transparency
Transparent
Crystal system
Hexagonal

Diagnostic features

## Identification Key diagnostic features of swedenborgite include its hexagonal crystal form, very high hardness (8 on the Mohs scale), vitreous luster, and occurrence in a specific geological environment. Its association with other rare minerals in the Långban mine is also characteristic. Due to its small size, identification often requires magnification. ## Distinguishing from Similar Minerals Swedenborgite can be confused with other colorless or yellowish minerals with hexagonal crystals, such as apatite, beryl, or phenakite. It is distinguished from apatite by its significantly higher hardness (8 versus 5). Distinguishing it from beryl (hardness 7.5-8) and phenakite (hardness 7.5-8) based on physical characteristics is difficult and often requires advanced analytical methods (e.g., EDS) to confirm the presence of antimony. However, its origin from a typical locality is a key indicator. ## Crystal Forms Swedenborgite forms well-developed, hexagonal crystals with a tabular or short-prismatic habit. Crystals are usually small, reaching sizes up to a few millimeters.

Geological environment

## Genesis Swedenborgite is a mineral of metamorphic origin. It forms in iron and manganese ore deposits that have undergone regional or contact metamorphism. It occurs in skarns and altered carbonate rocks, most often in calcite veins cutting hematite or hausmannite ores. ## Mineral Associations This mineral co-occurs with a number of other, often rare minerals, typical of the Långban deposit. The most common associations include: calcite, hausmannite, hematite, magnetite, richterite, bromellite, manganostibite, welinite, and tephroite. ## Localities The only confirmed and classic locality for swedenborgite in the world is its type locality – the Långban mine in the Långban district, Värmland region, Sweden. This is one of the most famous mineralogical sites in the world, renowned for its unique and rare minerals.

Rarity

Very rare

For collectors

## Quality Criteria For swedenborgite collectors, the most important quality criteria are the sharpness and development of the crystals. Specimens with well-defined, undamaged, hexagonal crystals with a distinct luster are most valued. Crystal size is also important – the larger, the more valuable. Transparency and aesthetic placement of the crystal on the rock matrix, especially in contrast with white calcite, enhance its attractiveness. ## Popular Localities All collectible swedenborgite specimens come from a single location in the world: the historic Långban mine in Sweden. This mine has been closed since the 1970s, meaning no new specimens enter the market, and available material comes exclusively from old collections.

Care and storage

## Cleaning Swedenborgite specimens, especially those embedded in calcite, should be cleaned very carefully. The safest method is to use a soft brush to remove dust. If necessary, distilled water can be used, but prolonged soaking should be avoided. Ultrasonic cleaning is not recommended due to the risk of damaging delicate crystals. ## What to Avoid Contact with acids, which can react with the surrounding rock (e.g., calcite), should be strictly avoided. Despite its high hardness, the mineral is brittle and should be protected from impacts and scratching by harder materials (e.g., diamond). There are no specific recommendations regarding light or temperature, but it is generally advisable to avoid extreme conditions. ## Storage The best way to store swedenborgite is to place it in a sealed "micromount" box, which protects small crystals from dust, moisture, and mechanical damage. Specimens should be stored separately to avoid contact with other minerals.

External references

Sources

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