Khanneshite
Chemical formula: (Na,Ca)<sub>3</sub>(Ba,Sr,Ce<sup>3+</sup>,Ca)<sub>3</sub>(CO<sub>3</sub>)<sub>5</sub>
Channeshite is a very rare mineral from the carbonate group, closely related to burbankite, occurring as hexagonal crystals.
Properties
- Mohs hardness
- 3.5
- Luster
- Vitreous to Resinous
- Streak
- White
- Density
- 3.31
- Cleavage
- Good on {1010}
- Fracture
- Conchoidal
- Transparency
- Translucent to Opaque
- Crystal system
- Hexagonal
Diagnostic features
## Identification Field identification of channeshite is practically impossible and requires advanced laboratory methods, such as X-ray diffraction (XRD) or chemical analysis (EDS/WDS). Preliminary suspicion can be based on its yellow color, hexagonal crystal form, and co-occurrence with other minerals typical of carbonatites. ## Distinguishing from Similar Minerals Channeshite is visually indistinguishable from burbankite, with which it forms a series. Differentiation requires chemical analysis to determine the dominance of barium over strontium. It can also be confused with other yellow carbonates or minerals from the apatite group found in similar environments. ## Crystal Forms It forms hexagonal, prismatic crystals with a columnar habit. They are often terminated by flat basal faces (pinacoid). It also occurs as granular aggregates.
Geological environment
## Genesis Channeshite is a magmatic mineral, crystallizing in the late stages of carbonatite formation – rare igneous rocks dominated by carbonates. It forms through hydrothermal processes associated with carbonatite intrusions. ## Mineral Associations This mineral occurs in association with other minerals typical of carbonatites, such as calcite, dolomite, barite, celestine, phlogopite, pyrochlore, and especially other rare carbonates like burbankite and carbocernaite. ## Localities The only confirmed and described locality for channeshite in the world is its type locality – the Channeshin (Khanneshin) volcanic complex in Helmand Province, southern Afghanistan.
Rarity
Extremely rare
For collectors
## Quality Criteria The most valuable channeshite specimens are those with well-formed, sharp, and as large as possible crystals, set on a contrasting rock matrix. The intensity of the yellow color and transparency also increase the specimen's value. Due to its extreme rarity, any authentic specimen, even in the form of granular aggregates, is valuable to specialized collectors. ## Popular Localities The only source of channeshite specimens is its type locality in Afghanistan. Access to this region is extremely limited due to political and security reasons, which means new specimens are practically unavailable on the market.
Care and storage
## Cleaning Utmost caution is recommended. The safest method is to use compressed air to remove dust. If necessary, a soft brush can be used. Contact with water, especially acidic water, is inadvisable due to the carbonate nature of the mineral. ## What to Avoid Contact with acids must be strictly avoided, as they can react violently with the mineral, leading to its destruction. Channeshite is brittle, so it should be protected from impacts and falls. Ultrasonic cleaning should not be used. ## Storage Channeshite specimens should be stored under stable conditions, in separate, padded collector boxes, to prevent abrasions and mechanical damage. They should be protected from dust and chemical contaminants.