Hanksite
Chemical formula: KNa<sub>22</sub>(S<sup>6+</sup>O<sub>4</sub>)<sub>9</sub>(CO<sub>3</sub>)<sub>2</sub>Cl
Hanksite is a rare mineral from the sulfate and carbonate groups, known for forming characteristic hexagonal crystals with double-terminated pyramids.
Properties
- Mohs hardness
- 3-3.5
- Luster
- Vitreous
- Streak
- White
- Density
- 2.56
- Cleavage
- Perfect on {0001}
- Fracture
- Conchoidal to uneven
- Transparency
- Transparent to translucent
- Crystal system
- Hexagonal
Diagnostic features
## Identification The key diagnostic feature of hanksite is its characteristic hexagonal crystal shape, often terminated by a double pyramid. Solubility in water is also a very important indicator. It tastes salty. Under shortwave UV light, it often exhibits creamy white or yellow fluorescence. ## Distinguishing from Similar Minerals It can be confused with other evaporites, such as halite, trona, or thermonatrite. However, it is distinguished by its specific crystal form (hexagonal, not cubic like halite) and its association with other minerals from Searles Lake. From quartz or calcite, it differs significantly in its much lower hardness and solubility in water. ## Crystal Forms The most common forms are single, hexagonal prismatic or tabular crystals, terminated by hexagonal pyramids. They often occur as intergrown groups and aggregates. Crystals may contain inclusions of other minerals or fluid inclusions.
Geological environment
## Genesis Hanksite is an evaporite mineral, meaning it crystallizes from highly saline waters in desert and arid conditions. It forms in the sediments of drying alkaline lakes, rich in sulfates, carbonates, and sodium chlorides. ## Mineral Associations This mineral occurs in association with other evaporites. Most commonly, these include halite, borax, trona, nahcolite, northupite, sulfohalite, and thenardite. Hanksite specimens often contain inclusions of these minerals. ## Localities The most important and classic locality for hanksite worldwide is Searles Lake in San Bernardino County, California, USA. Most collector specimens come from there. It is also found in other similar environments, such as Soda Lake (California), in some salt lakes in Turkey (near Ankara), and in Uganda (Lake Katwe).
Rarity
Not very common
For collectors
## Quality Criteria The most valued by collectors are large, well-formed, transparent, and undamaged crystals. Specimens with sharp edges and smooth faces, without white weathering efflorescence, are highly prized. Interesting inclusions (e.g., of other minerals) and aesthetically pleasing intergrowths of several crystals enhance their attractiveness. Specimens exhibiting strong fluorescence are also sought after. ## Popular Localities By far the most desirable specimens come from the classic locality - Searles Lake, California. This is where the largest and best-formed crystals are obtained, which set the standard for this mineral in the collector's market.
Care and storage
## Cleaning Hanksite specimens should only be cleaned dry, using a soft brush to remove dust. Compressed air can be used from a safe distance. It is absolutely forbidden to use water or any liquids, as the mineral is soluble in them. ## What to Avoid Contact with water, water vapor, and high humidity must be strictly avoided, as these can damage or completely dissolve the specimen. It should be protected from acids and other chemicals. It is a brittle mineral, sensitive to impacts and scratches. ## Storage Hanksite collections should be stored in a dry place, preferably in tightly sealed containers (e.g., "perky box" type) or in display cases with a moisture absorber (silica gel). Exposure should be away from sources of moisture and sudden temperature changes.