Paulišite
Chemical formula: Ca₂Zn²⁺(CO₃)₃(H₂O)₂
Paulišite is a rare hydrated calcium zinc carbonate, forming colorless or white, acicular crystals with a silky luster.
Properties
- Mohs hardness
- 4-0
- Luster
- Silky
- Streak
- white
- Density
- 2.756
- Cleavage
- Distinct in the direction of elongation
- Transparency
- Transparent
- Crystal system
- Monoclinic
Diagnostic features
## Identification Paulišite can be recognized by its characteristic form – it creates very fine, acicular or fibrous crystals, often gathered in radial or tangled aggregates. Its colorless or white color, silky luster, and occurrence in paragenesis with other secondary zinc and calcium minerals are key indicators. It reacts violently with acids, which is typical for carbonates. ## Distinguishing from Similar Minerals It can be confused with other acicular carbonates, such as aragonite or hydrozincite. It differs from aragonite by its lower hardness and the presence of zinc in its composition (requires chemical analysis). From hydrozincite, which often co-occurs, it differs by the presence of calcium and a different crystal structure. Certain identification almost always requires advanced analytical methods, such as X-ray diffraction (XRD). ## Crystal Forms Crystals are strongly elongated, acicular, up to 1 mm long. They form characteristic aggregates with a radial, fibrous, or tangled habit, resembling tufts of cotton.
Geological environment
## Genesis Paulišite is a secondary mineral, formed in the oxidation (weathering) zones of ore deposits, especially those rich in zinc and calcium. It forms under low-temperature conditions as a result of carbon dioxide-rich waters acting on earlier minerals. ## Mineral Associations At the type locality (Kutná Hora), paulišite co-occurs with minerals such as hydrozincite, aragonite, calcite, sphalerite, galena, and pyrite. ## Localities The only confirmed and described occurrence of paulišite in the world is its type locality – the historical Staročeské Lode ore deposits in the Kutná Hora region of the Czech Republic.
Rarity
Extremely rare
For collectors
## Quality Criteria As a "micromount" type mineral, the collector's value of paulišite depends on the richness and aesthetics of the aggregates on the rock matrix. The most prized specimens are those with well-formed, dense, and undamaged clusters of acicular crystals. Contrast with a darker host rock enhances visual appeal. Due to its extreme rarity, every well-documented specimen has significant scientific and collector value. ## Popular Localities The only source of specimens is the type locality in Kutná Hora, Czech Republic. Material from this location is extremely difficult to obtain.
Care and storage
## Cleaning Paulišite specimens are extremely delicate and brittle. They should be cleaned only with great care, using compressed air to remove dust. Any contact with water, even distilled, or a brush can permanently damage the fine, acicular crystals. ## What to Avoid Avoid contact with all chemicals, especially acids, which will rapidly dissolve it. The mineral is sensitive to shocks and mechanical damage. It should not be heated or exposed to prolonged moisture. ## Storage It is recommended to store specimens in closed, padded "micromount" boxes to protect them from dust, moisture, and mechanical damage. Display should be in stable conditions, away from vibrations and direct sunlight.