Stenonite
Chemical formula: Sr<sub>2</sub>Al(CO<sub>3</sub>)F<sub>5</sub>
Stenonite is a very rare strontium aluminum fluoride carbonate, forming tiny, colorless crystals with a vitreous luster.
Properties
- Mohs hardness
- 3.5
- Color
- Colourless, white
- Luster
- Vitreous
- Streak
- White
- Density
- 3.86
- Cleavage
- Good on {001} {120}
- Fracture
- Uneven
- Transparency
- Transparent,Translucent
- Crystal system
- Monoclinic
Diagnostic features
## Identification Identifying stenonite in the field is practically impossible due to its extreme rarity and small crystal sizes. Identification requires advanced laboratory methods such as X-ray diffraction (XRD) and chemical analysis (EDS/WDS). Visually, it might be suspected in association with other rare minerals from Ivigtut if tiny, colorless, tabular crystals are observed. ## Distinguishing from Similar Minerals It can be confused with other colorless, microcrystalline minerals found in the same environment, such as cryolite, ralstonite, or jarlite. Differentiation without specialized equipment is impossible. Stenonite is distinguished by its unique combination of strontium, aluminum, fluorine, and a carbonate group in its composition. ## Crystal Forms Stenonite crystals are typically tabular, flattened parallel to {001}, or short prismatic. They often form fan-shaped or radial aggregates.
Geological environment
## Genesis Stenonite is a mineral of hydrothermal origin. It forms in the late stages of crystallization in cryolite-carbonate deposits that have undergone metasomatism. Its only known locality, Ivigtut, is a unique magmatic complex associated with a fluorine-rich granitic pegmatite. ## Mineral Associations This mineral co-occurs with other rare minerals from the cryolite deposit. It is most commonly associated with jarlite, thomsenolite, ralstonite, gearksutite, as well as cryolite, fluorite, and siderite. ## Localities The only confirmed locality for stenonite in the world is the historic cryolite mine in Ivigtut, southwestern Greenland. This mine is currently flooded and inaccessible, making the acquisition of new specimens impossible.
Rarity
Extremely rare
For collectors
## Quality Criteria The quality of a stenonite specimen primarily depends on the size and development of the crystals and the abundance of their occurrence on the rock matrix. The most prized specimens are those with clearly visible, sharp, transparent crystals forming aesthetic aggregates. Association with other rare minerals from this locality is also important. ## Popular Localities All collector specimens originate from a single, historic locality: the Ivigtut mine in Greenland. Material available on the market comes exclusively from old collections.
Care and storage
## Cleaning Stenonite specimens are extremely delicate and small. Cleaning, if absolutely necessary, should be limited to very careful use of compressed air to remove dust. Contact with water and any chemical agents should be avoided. ## What to Avoid Avoid ultrasonic cleaners, acids, solvents, and sudden temperature changes. The mineral is soft and easily susceptible to mechanical damage. Due to its chemical composition, reactions with acids are probable. ## Storage Stenonite specimens should be stored under stable conditions, in enclosed "micromount" containers, to protect them from dust, moisture, and physical damage. Avoid exposure to direct sunlight, although there is no evidence of fading.