Celleriite
Chemical formula: ◻(Mn²⁺₂Al)Al₆(Si₆O₁₈)(BO₃)₃(OH)₃(OH)
Celleriite is a very rare mineral from the tourmaline group, distinguished by its unique chemical composition with dominant manganese.
Properties
- Mohs hardness
- 7
- Color
- Violet to gray-blue, dark brownish-green
- Luster
- Vitreous
- Streak
- White
- Density
- 3.13
- Cleavage
- None
- Fracture
- Conchoidal
- Transparency
- Transparent to Translucent
- Crystal system
- Trigonal
Diagnostic features
## Identification Amateur identification of celleriite is practically impossible and requires advanced analytical methods, such as chemical analysis (EDS/WDS) and crystallographic studies (XRD). Preliminary identification is based on crystal habit (typical for tourmalines), color (orange-yellow), and co-occurrence with other pegmatitic minerals from Elba. ## Distinguishing from Similar Minerals It can be confused with other tourmalines of similar color, especially elbaite, dravite, or schorl. The only way to definitively distinguish it is through chemical analysis, which will reveal celleriite's unique position as a tourmaline with a vacancy at the X site and dominance of manganese and aluminum at the Y and Z sites. ## Crystal Forms It forms short to elongated prismatic crystals, often with striations along the main axis. The cross-section of the crystals is characteristically rounded, approaching a triangle.
Geological environment
## Genesis Celleriite forms in genetically complex LCT-type (lithium, cesium, tantalum) granitic pegmatites. It is a product of crystallization from boron-, manganese-, and aluminum-rich fluids in the late stages of pegmatite evolution. ## Mineral Associations This mineral co-occurs with other minerals typical of Elba pegmatites, such as quartz, orthoclase, albite (cleavelandite variety), elbaite, schorl, lepidolite, pollucite, petalite, cassiterite, and columbite-(Mn). ## Localities The only confirmed locality for celleriite in the world is its type locality – the pegmatites in the San Piero in Campo area on Elba Island, in the province of Livorno, Italy.
Rarity
Extremely rare
For collectors
## Quality Criteria As a mineral primarily of micromount significance, the most important quality criterion is the crystal habit and sharpness, even if they are small. Specimens with well-defined, transparent crystals of intense, orange-yellow color are highly valued. Particularly valuable are samples where celleriite is embedded in a contrasting matrix, for example, on white albite. ## Popular Localities The only known and most prized specimens come from the type locality on Elba Island, Italy. Every specimen from this locality is considered extremely valuable for advanced collectors specializing in mineral systematics or tourmaline group minerals.
Care and storage
## Cleaning Specimens should only be cleaned mechanically, using a soft brush to remove dust. Due to its rarity and potential instability, contact with water and chemical agents should be avoided. If liquid is necessary, only pure distilled water or alcohol is recommended, applied in minimal amounts and quickly dried. ## What to Avoid Ultrasonic cleaners, strong detergents, acids, and bases should be absolutely avoided. The mineral is brittle, so it must be protected from impacts and sudden temperature changes. It should not be exposed to prolonged intense sunlight, which may affect its color. ## Storage Celleriite specimens, being extremely rare and valuable, should be stored in separate, padded display boxes to prevent abrasions and mechanical damage. It is best to keep them in stable room conditions, away from moisture and direct light.