Škáchaite
Chemical formula: CaCo²⁺(CO₃)₂
Škáchaite is a very rare calcium cobalt carbonate, forming pink, spherulitic aggregates in calcite.
Properties
- Mohs hardness
- 3.5-4
- Color
- Pale to bright pink
- Luster
- Vitreous
- Streak
- white
- Density
- 3.140
- Cleavage
- <mi>{10_11}</mi>
- Transparency
- Translucent
- Crystal system
- Trigonal
Diagnostic features
## Identification Identification of škáchaite is possible only through advanced analytical methods, such as Raman spectroscopy or chemical analysis by electron microprobe (EDS/WDS). Visually, at the occurrence site, it can be suspected based on its pink color and spherulitic form within calcite. ## Distinguishing from Similar Minerals It can be confused with other pink carbonates, such as cobaltoan calcite (a cobalt-rich variety of calcite) or spherocobaltite (CoCO₃). It differs from cobaltoan calcite by its ordered crystal structure (dolomite group), and from spherocobaltite by the presence of calcium in its composition. Definitive differentiation requires specialized studies. ## Crystal Forms Škáchaite exclusively forms spherulitic, radial aggregates. It has not been observed in the form of well-developed, single crystals.
Geological environment
## Genesis Škáchaite forms under low-temperature hydrothermal conditions. In the only known locality, it crystallized in fissures of volcanic rocks (melaphyre), filled with calcite. ## Mineral Associations This mineral co-occurs directly with calcite. In the broader geological environment of the type locality, minerals from the zeolite group, quartz, goethite, and clay minerals are also present. ## Localities The only confirmed occurrence worldwide (type locality) is the melaphyre quarry in Věžná, near Žďár nad Sázavou, in the Vysočina Region of the Czech Republic.
Rarity
Extremely rare
For collectors
## Quality Criteria As an extremely rare micromineral, every analytically confirmed specimen is valuable. Collectible value is primarily determined by the intensity of the pink color, the size and distinctness of the spherulitic aggregates, and their contrast with the surrounding white calcite. The most desirable specimens are those with several well-defined, richly colored spherulites. ## Popular Localities The only source of specimens is the type locality in Věžná, Czech Republic. Finding a new specimen is an event in the world of micromineral collectors.
Care and storage
## Cleaning Škáchaite specimens should not be cleaned mechanically or chemically due to their delicacy and embedding in calcite. If dust removal is necessary, a photographic air blower can be used to dislodge loose particles. ## What to Avoid Contact with acids (even weak ones, like vinegar) must be strictly avoided, as they will rapidly dissolve both škáchaite and the surrounding calcite. The mineral should be protected from moisture, ultrasound, and all chemicals. ## Storage Specimens should be stored in stable conditions, in a closed "micromount" box, to protect them from dust, mechanical damage, and sudden temperature changes.