Plechovite

Chemical formula: Ca₂[K(H₂O)]KBe₃Si₁₂O₃₀

Plechovite is an extremely rare beryllosilicate from the osumilite group, discovered in Poland (Jordanów Śląski). It is distinguished by its yellowish color and occurs as translucent microcrystals.

## Characteristics Plechovite is a very rare silicate mineral belonging to the osumilite group. It forms translucent crystals with a characteristic yellowish color. Due to its rarity, specimens of this mineral usually take the form of microscopic grains or very fine crystals embedded in the host rock. ## Physical properties The mineral crystallizes in the hexagonal crystal system. Its Mohs hardness is 6. The density of plechovite has been precisely determined to be 2.626 g/cm³. The mineral is translucent and leaves a white streak. No fracture has been observed in studies to date. ## Colors and varieties Plechovite occurs in a yellowish color. As a mineral known from a single locality, it has no described color varieties or trade names. ## History and name Plechovite is a new mineral whose type locality is a granite quarry in Jordanów Śląski in Lower Silesia, Poland. It was approved by the IMA and included in the systematics as a new representative of the osumilite group, expanding knowledge about beryllosilicates occurring in granitoid rocks. ## Uses Plechovite has no industrial application. It is exclusively an object of scientific research and a highly desirable specimen for advanced collectors of rare minerals and systematists.

Properties

Mohs hardness: 6-0
Color: yellowish
Streak: white
Density: 2.626
Fracture: None observed
Transparency: Translucent
Crystal system: Hexagonal

Diagnostic features

## Identification Macroscopic identification of plechovite is extremely difficult due to the small size of the crystals. The yellowish color and occurrence in the specific granite environment in Jordanów Śląski serve as an initial clue. Advanced analytical studies, such as X-ray diffraction (XRD) and electron microprobe chemical analysis, are required for unambiguous identification. ## Distinction from similar minerals Plechovite can be visually confused with other yellowish silicates occurring in granite rocks, including other members of the osumilite group. Distinguishing it from related minerals requires precise determination of the chemical composition, in particular confirming the presence of calcium, potassium, and beryllium in the structure. ## Crystal habit It crystallizes in the hexagonal crystal system. It forms very fine crystals or grains embedded in the rock, typical of microcrystals from this silicate group.

Geological environment

## Origin Plechovite is a mineral associated with the granite rock environment. It forms under specific geochemical conditions requiring an appropriate concentration of beryllium, calcium, and potassium in the crystallizing solutions. ## Mineral associations It occurs in paragenesis with minerals of granite rocks. The exact composition of the association depends on the specifics of the zone at the type locality. ## Localities The only confirmed occurrence of plechovite in the world (type locality) is the granite quarry in Jordanów Śląski, located in Wrocław County, Lower Silesia, Poland.

Rarity

Extremely rare

For collectors

## Quality criteria In the case of such rare minerals, the main criterion of collector value is the confirmed authenticity of the specimen from the type locality. Rock fragments with crystals clearly visible under a microscope showing a distinct yellowish color are valued. ## Popular localities The only source of specimens of this mineral is its type locality - the granite quarry in Jordanów Śląski. Specimens from there go almost exclusively to specialized systematic collections.

Care and storage

## Cleaning Specimens containing plechovite should be cleaned very carefully, preferably using a soft brush and compressed air. If a liquid must be used, distilled water is recommended. Brushing that could damage the fine crystals should be avoided. ## What to avoid The use of aggressive chemicals, including acids and bases, which can react with the mineral or host rock, must be strictly avoided. Specimens must be protected from mechanical shocks. ## Storage The mineral should be stored in a dry place, in a closed collection box (micromount type), which will protect it from dust and accidental damage.

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External references

https://www.mindat.org/min-499620.html