Tululite
Chemical formula: Ca₁₄(Fe³⁺,Al)(Al,Zn²⁺,Fe³⁺,Si,P,Mn³⁺,Mg)₁₅O₃₆
Tululite is a very rare, transparent, yellowish-green mineral discovered in Jordan, belonging to the mayenite group.
Properties
- Mohs hardness
- 6.5
- Luster
- Vitreous
- Streak
- White
- Density
- 3.826
- Cleavage
- None
- Fracture
- Irregular/Uneven
- Transparency
- Transparent
- Crystal system
- Isometric
Diagnostic features
## Identification Identifying tululite under amateur conditions is practically impossible. It requires advanced analytical techniques, such as X-ray microanalysis (EDS/WDS) to confirm its complex chemical composition. The characteristic yellowish-green color and occurrence in a specific geological environment can be an indication. ## Distinguishing from Similar Minerals This mineral may be confused with other microscopic minerals from the mayenite group or other yellow minerals occurring in similar parageneses. Definitive differentiation is only possible based on chemical and crystallographic analysis. ## Crystal Forms Tululite crystallizes in the isometric system, forming very small, granular crystals, often with a rhombic dodecahedral habit. They usually occur as single, isolated grains within the host rock.
Geological environment
## Genesis Tululite forms as a result of pyrometamorphic processes occurring in carbonate rocks. Its formation is associated with extremely high temperatures, exceeding 800°C, which lead to the combustion and recrystallization of rocks, similar to cement kilns. It occurs in rocks of the Hatrurim Formation (also known as the Mottled Zone Formation). ## Mineral Associations This mineral co-occurs with other rare high-temperature minerals, such as larnite, brownmillerite, mayenite, shulamitite, ye'elimite, and spurrite. ## Localities The only confirmed locality of tululite in the world is its type locality: the Tulul al Hammam area in the Daba-Siwaqa complex in Jordan.
Rarity
Extremely rare
For collectors
## Quality Criteria As a microscopic mineral, tululite is primarily valued by collectors specializing in "micromount" specimens and rare and systematic minerals. Specimens showing well-formed, though still microscopic, crystals with intense color, set on a contrasting rock matrix, are most highly prized. The certainty of the specimen's identification is also crucial. ## Popular Localities The only source of tululite specimens is its type locality in Jordan. Material from this location is extremely difficult to acquire and appears on the collector's market sporadically.
Care and storage
## Cleaning Tululite specimens, due to their microscopic crystal sizes, usually do not require cleaning. If necessary, use compressed air to remove dust. Avoid contact with water and chemical agents. ## What to Avoid Protect the mineral from all chemicals, acids, and bases. Due to its fragility, avoid ultrasound, vibrations, and sudden temperature changes. It should not be subjected to mechanical processing. ## Storage Tululite specimens should be stored in specialized, sealed "micromount" boxes that protect them from dust, moisture, and mechanical damage. Storage under stable room conditions is entirely sufficient.